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ORIGINAL Slusanschi ARTICLE et al Validation of a Romanian Version of the Short Form of the Oral Health Impact Profile (...

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ORIGINAL Slusanschi ARTICLE et al

Validation of a Romanian Version of the Short Form of the Oral Health Impact Profile (OHIP-14) for Use in an Urban Adult Population Oana Slusanschia/Ruxandra Morarub/Liliana Garneatac/Gabriel Mircescud/ Marian Cuculescue/Elena Preoteasaf Purpose: To obtain a valid Romanian version of the OHIP-14 for use among Romanian adults, either in Romania or abroad. Materials and Methods: The Romanian version of the OHIP-14 was obtained through the back translation technique and pre-tested in a pilot study. Subsequently, it was self-administered to 187 adults who also underwent a clinical examination. Cronbach alpha was used to check the internal consistency and reliability analysis and validity tests were used to determine the psychometric properties of the questionnaire. Results: The Cronbach alpha coefficient obtained was 0.88. Inter-item correlation coefficients were between 0.01 and 0.74; item-total correlation values ranged between 0.25 and 0.77. There were statistically significant associations (p ≤ 0.001) between the respondents’ self-perceived oral health (r = 0.41), the dental treatment need (r = 0.35) and the mean of the OHIP-14 total scores. Similar statistically significant associations (p ≤ 0.001) existed between the OHIP-14 total scores mean and the clinical data – the number of decayed (D) and of missing (M) teeth and the prosthetic treatment need – proving the construct validity of the questionnaire. The subscales ‘physical pain’ and ‘psychological disability’ have the most important impact on the overall OHIP-14 score. The subscales ‘social disability’ and ‘handicap’ seem to make the least contribution to the overall OHIP-14 score. Conclusion: The Romanian version of the OHIP-14 is a valid and reliable questionnaire that can be used in future studies. Key words: linguistic and cultural validation, OHIP-14, oral-health related quality of life Oral Health Prev Dent 2013;11:235-242 doi: 10.3290/j.ohpd.a30166

a

Assistant Lecturer, Department of Preventive Dentistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

b

Clinical Lecturer with the Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, UK.

c

Assistant Lecturer, Department of Nephrology and Internal Medicine, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

d

Professor, Department of Nephrology and Internal Medicine, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

e

Senior Lecturer, Department of Preventive Dentistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

f

Professor, Department of Removable Prosthetics, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

Correspondence: Oana Slusanschi, Department of Preventive Dentistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, Str. Fainari nr. 7, bl. B4, ap. 9, sector 2, 021221 Bucharest, Romania. Tel: +40-722-266-279, Fax: +40-21-243-2739. Email: [email protected]

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Submitted for publication: 12.06.12; accepted for publication: 02.08.12

T

he Oral Health Impact Profile (OHIP) scale is one of the main quality of life scales used to measure the impact of oral health. OHIP was based on the oral health model adapted specifically for dentistry by Locker (1988), originally proposed by the World Health Organisation for general health. The model suggests a hierarchy of impacts that can stem from oral disease. Concerning the oral health related quality of life, Locker (1988) argued that quality of life indicators related to oral health could be defined as measurements of the degree to which dental problems and oral disorders interfere with an individual’s normal functioning. Developed by Slade and Spencer (1994), OHIP allows the exploration of the relationship between quality of life and oral health status. While the original OHIP scale used 49 questions (Slade and Spencer, 1994), a shorter version of the scale was derived consisting of 14 questions, making it more

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practical to use in the context of a clinical trial (Slade, 1997). The OHIP-14 was statistically and pragmatically proven to be as reliable as the original version (Slade, 1997). Due to its reliability, precision and validity, OHIP has been preferred for measuring the social impact of various oral conditions and diseases worldwide. Thus, it has been translated into many languages (Chinese, Czech, Finnish, French, German, Greek, Hungarian, Japanese, Malaysian, Persian, Portuguese, Spanish, Swedish, Turkish, etc.) and used with a relative degree of cross-cultural validity (Allison et al, 1999). The aim of this study was to obtain a valid translation of the OHIP-14 in Romanian and to test its validity and reliability for future oral health-related quality of life studies dedicated to the Romanian adult population living either in Romania or abroad.

MATERIALS AND METHODS The OHIP-14 is a self-administered questionnaire which indicates quality of life. It is directed towards seven impact dimensions, namely: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability and handicap. The responses are made on a 5-point Likert scale and are coded as very often (score 4), fairly often (score 3), occasionally (score 2), hardly ever (score 1) and never (score 0). The questions usually refer to problems experienced within the last twelve months, but this can be changed to fit study requirements. Streiner and Norman (2008) indicate that ‘the goal of translation of a questionnaire is to achieve equivalence between the original version and the translated version of the scale’, i.e. conceptual, item, semantic, operational and measurement equivalence. Thus, the validation process consisted of two phases: the linguistic and cultural adaptation of the questionnaire, in which conceptual, item, semantic and operational equivalence were established, and the main study, in which measurement equivalence was assessed.

Linguistic and cultural adaptation This first phase of the validation process consisted of two steps: obtaining a first form of the OHIP-14 and testing this form for face and content validity in a pilot study.

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A team of two dentists, a native English-speaking professor and a psychologist discussed and established that, for the OHIP-14, there are no major conceptual differences when taking into consideration oral health and quality of life. Further, all 14 items were ‘relevant and acceptable’ (Streiner and Norman, 2008) for the selected studied population. The semantic equivalence was obtained according to the back-translation technique. The original English version of the OHIP-14 was translated into Romanian by two bilingual dentists who were native Romanians and fluent in English, thus obtaining two separate translations of the questionnaire. The two dentists discussed and agreed upon a single version of the translation. This first version was then translated back into English by a native speaker of English, a professor at the University of Bucharest, who speaks Romanian fluently and has lived in Romania for several years. This native speaker of English was shown the original English version of the questionnaire only after finishing his translation. Consequently, the two dentists, the English professor and the psychologist, taking into consideration Romanian linguistic and cultural issues, discussed and agreed upon a first form of the Romanian version of the OHIP-14. As both the instructions and the mode of administration of the original OHIP-14 could be applied on the target population, the operational equivalence was also established. The pilot study was carried out on a sample of 30 Romanian adults visiting one dental practice in Bucharest. The participants were asked whether they had any difficulties in understanding some of the questions and inquiries were made about certain words and phrases (much debated during the translation process) to see if their meaning was correctly understood. The pilot-tested Romanian form of the questionnaire was used in the main study.

Main study The cross-sectional epidemiological study was conducted in Bucharest in 2011. The studied sample was the same as one used in a larger study on the oral health of haemodialysis patients and consisted of adults attending a haemodialysis clinic and patients attending a private dental practice, both in Bucharest. All participants gave their informed written consent. Persons with acute oral problems and malignancies were not included in the study.

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Participants underwent an oral examination performed by the same dentist. The clinical data gathered included: the Silness and Löe Plaque Index, the clinical attachment level (CAL), the periodontal pocket depth (PPD), the DMFT index (the total number of decayed, missing and filled teeth), the type of existing prosthesis/prosthetic treatment and the need for prosthetic treatment. Questions regarding the subjects’ education, smoking habits, oral hygiene and visits to the dentist were asked by the doctor performing the clinical examination. Participants were also asked about their self-perceived oral health and need of dental treatment; in the absence of a standard accepted procedure for assessing construct validity, this information was used to test the construct validity of the Romanian version of the OHIP-14 (MonterroMartin et al, 2009; Papagiannopoulou et al, 2012). The tested Romanian version of the OHIP-14 was self-administered after the completion of the oral examination, and participants were asked to respond to the questions bearing in mind their experience during the past year.

Data analysis The data analysis was performed using the Statistical Package for Social Sciences (SPSS), version 16 (Chicago, IL, USA). The OHIP-14 score was calculated using the additive method. The Cronbach alpha coefficient together with the alpha value if one item is removed, inter-item and item-total correlation coefficients were used in order to assess the internal consistency of the tested version. Spearman correlations and ANOVA were used to assess convergent and construct validity by comparing OHIP-14 scores and data regarding perceived oral health, dental treatment need and clinical parameters describing oral health. In addition, possible statistically significant differences between groups of subjects related to age, sex, place of residence and education were analysed using ANOVA and the Mann-Whitney test. A P-value lower than 0.05 was considered statistically significant.

RESULTS

study. Only 155 haemodialysis patients and 32 patients from the dental practice agreed to participate and gave their informed consent. The total number of participants was 187, the mean age of the group was 59.43 ± 12.8, 58.71% were male, 85.6% (160) live in an urban area, 40.6% (76) had secondary education, while 33.2% (62) had higher education. In terms of behaviour, 68.4% (128) went to the dentist when a perceived oral problem persisted, while 24.6% (46) went to the dentist as soon as they noticed there was a dental problem, and only 7% (13) went to the dentist on a regular basis. When asked about their last visit to the dentist, 12.3% (23) reported going sometime within the last 6 months, 13.9% (26) reported going sometime between 6 months and 1 year ago, 15% (28) said they went to the dentist between 1 and 2 years ago and 58.8 % (110) said their last visit to the dentist was more than 2 years ago. Regarding their oral hygiene habits, 54% (101) subjects brushed twice a day, 33.2% (62) brushed once a day, 12.8% (19) brushed occasionally or never and 25.7% (48) used a mouthwash. The clinical examination revealed 11.8% (22) edentulous subjects; the mean plaque index for the dentate remainder of the group was 1.12. The mean DMFT index was 16.4 ± 8.5 with a mean of 1.59 ± 2.3 for decayed teeth, a mean of 10.84 ± 8.8 for missing teeth and 3.96 ± 4.8 for filled teeth. Severe periodontitis (CAL ≥ 5 mm) was found in 63.6% (119), while 19.8% (37) subjects had moderate periodontitis (CAL > 2 mm and < 5 mm) and only 3.2% (6) subjects had either mild or no periodontitis (CAL ≤ 2 mm). With regard to their perception of their oral health, 26.7% (50) participants considered their oral health to be bad, 28.3% (53) considered it to be acceptable, 34.8% (65) described their oral health as good and 10.2% (19) considered it to be very good. Dental treatment need was perceived by 61.5% (115) of the subjects. The completed copies of the questionnaires have no missing data, as we checked for unanswered questions after each participant finished completing the questionnaire. Seven subjects missed one or two questions and we asked them to fill them in. No subjects had problems understanding the questions.

One hundred sixty patients undergoing haemodialysis and 40 patients visiting a dental practice during a 1-month period were initially selected for the

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Validity The content validity of the Romanian version was established during the pilot study. That is, the group of experts decided that the face and content validity of the original English version was not lost through the translation and cultural adaptation of the questionnaire. The analysis of the oral health-related quality of life data collected from the completed questionnaires reveals a mean of 0.57 ± 0.68, with a 95% confidence interval of the mean of 0.47–0.67 for the overall OHIP-14 score (i.e. the mean score of all 14 items, Q1-Q14). Physical pain, defined as the mean of Q3 and Q4, and psychological disability, defined as the mean of Q9 and Q10, had the strongest impact on the overall OHIP-14 score (i.e. detrimental effect on quality of life). On the other hand, the weakest impact on the overall OHIP-14 score was due to social disability, defined as the mean of Q11 and Q12, and handicap, defined as the mean of Q13 and Q14. Table 1 presents an overview of all the means, standard deviations and 95% confidence intervals of the mean (95% CI) values of the OHIP-14 subscale scores. The Cronbach alpha of the OHIP-14 questionnaire is 0.88, which is considered to be very good

(Streiner and Norman, 2008). The Cronbach alpha value shows no significant increase if one of the items is removed, thus demonstrating the relevance of all 14 items. The analysis of the inter-item correlation matrix depicted in Table 2 shows positive correlations for all pairs defined by the 14 items. The value of coefficients ranges from 0.01 between items 1 and 14 to 0.74 between items 5 and 10. The item-total correlation analysis revealed acceptable values, all being above 0.2 (Streiner and Norman, 2008) and ranging between 0.25 for item 3 to 0.77 for item 10. The inter-item (Table 3) and item-total correlations for the seven subscales of OHIP-14 reveal a Cronbach alpha of 0.87, and all inter-item and itemtotal correlations exhibit a statistically significant increase. This is a supplementary validation of the consistency of the OHIP-14 scale and of the relevance of the seven subscales, as shown in Table 3. The respondents’ perceived oral health on the one hand and the mean value of the OHIP-14 total score and subscale scores on the other show a negative correlation. That is, the mean values increase as the perceived oral health changes from very good to bad. Moreover, subjects reporting a need for dental treatment have higher subscale and total OHIP-14 mean scores when compared to

Table 1 Mean, standard deviation and 95% confidence interval of the mean (95% CI) of the OHIP-14 subscale scores OHIP-14 subscale

Question

Mean, SD and 95% CI of subscale scores

Functional limitation

Q1: Trouble with pronunciation Q2: Worsened sense of taste

0.44 SD = 0.72 95% CI = 0.34–0.55

Physical pain

Q3: Painful aching in the mouth Q4: Discomfort while eating

0.87 SD = 0.86 95% CI = 0.75–0.99

Psychological discomfort

Q5: Feeling self-conscious Q6: Feeling tense

0.71 SD = 1.11 95% CI = 0.55–0.87

Physical disability

Q7: Unsatisfactory diet Q8: Interrupted meals

0.58 SD = 1.01 95% CI = 0.44–0.73

Psychological disability

Q9: Difficult to relax Q10: Being embarrassed

0.83 SD = 1.16 95% CI = 0.67–1.00

Social disability

Q11: Being irritable Q12: Difficult to do usual jobs

0.25 SD = 0.69 95% CI = 0.15–0.34

Handicap

Q13: Life less satisfying Q14: Inability to function at all

0.31 SD = 0.64 95% CI = 0.22–0.40

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ured clinical data and the corresponding question were not directly related, as presented in Table 4. A positive dependence was observed between the severity of the periodontal disease and the mean total score (P = 0.08, ANOVA test for linearity). This dependence showed an increase in the mean OHIP-14 scores as the severity of the periodontal disease increased. There was no statistically significant difference between respondents from the haemodialysis clinic and those from the dental clinic. Neither were statistically significant differences found to be induced by age, sex, education or residence.

the subjects specifying no need for dental treatment. In both cases, Spearman’s rank correlation coefficients are negative and statistically significant, thus proving the convergent validity of the Romanian version of the OHIP-14. Further statistical analysis showed a logical correlation between the oral status as described by the clinical data – number of decayed (D) and missing teeth (M), the need for prosthetic treatment – and the mean scores of subscales and total OHIP14, thus proving construct validity. Generally, Spearman rho correlations were statistically significant with minor exceptions, mostly where the meas-

Table 2 Reliability analysis: inter-item correlation matrix for the 14 questions Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q8

Q9

Q10

Q11

Q12

Q13

Q1

1.00

Q2

0.15

1.00

Q3

0.17

0.04

1.00

Q4

0.28

0.28

0.17

1.00

Q5

0.12

0.30

0.17

0.49

1.00

Q6

0.22

0.21

0.22

0.43

0.55

1.00

Q7

0.28

0.32

0.17

0.48

0.47

0.39

1.00

Q8

0.34

0.26

0.26

0.38

0.38

0.48

0.51

1.00

Q9

0.20

0.22

0.23

0.45

0.57

0.65

0.52

0.61

1.00

Q10

0.23

0.32

0.18

0.55

0.74

0.63

0.48

0.50

0.62

1.00

Q11

0.20

0.17

0.13

0.32

0.27

0.26

0.26

0.45

0.29

0.42

1.00

Q12

0.20

0.36

0.13

0.31

0.38

0.19

0.34

0.55

0.38

0.39

0.53

1.00

Q13

0.22

0.38

0.16

0.40

0.57

0.51

0.60

0.50

0.54

0.62

0.42

0.58

1.00

Q14

0.01

0.08

0.13

0.16

0.13

0.32

0.13

0.34

0.40

0.26

0.31

0.46

0.35

Q14

1.00

Table 3 Reliability analysis: inter-item correlation matrix for the 7 subscales Q1Q2

Q3Q4

Q5Q6

Q7Q8

Q9Q10

Q11Q12

Q1Q2

1.00

Q3Q4

0.35

1.00

Q5Q6

0.32

0.51

1.00

Q7Q8

0.46

0.51

0.56

1.00

Q9Q10

0.36

0.55

0.82

0.67

1.00

Q11Q12

0.35

0.35

0.36

0.52

0.48

1.00

Q13Q14

0.35

0.38

0.59

0.62

0.66

0.62

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Q13Q14

1.00

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Table 4: Reliability analysis: correlations (Spearman rho) between perceived aspects of oral health, clinical data and OHIP-14 subscales and total score means OHIP-14 subscales and total mean values Functional limitation

M

Prosthetic treatment need, maxilla

Prosthetic treatment need, mandible

r=0.22**

r=0.15*

r=0.17*

r=0.13

p=0.002

p=0.002

p=0.042

p=0.022

p=0.079

r=-0.31**

r=-0.35**

r=0.26**

r=0.05

r=0.28**

r=0.27**

p=0.000

p=0.000

p=0.000

p=0.494

p=0.000

p=0.000

r=-0.37**

r=-0.29**

r=0.23**

r=0.27**

r=0.36**

r=0.26**

p=0.000

p=0.000

p=0.001

p=0.000

p=0.000

p=0.000

r=-0.30**

r=-0.17*

r=0.17*

r=0.24**

r=0.21**

r=0.23**

p=0.000

p=0.022

p=0.019

p=0.001

p=0.004

p=0.002

r=-0.35**

r=-0.24**

r=0.25**

r=0.17*

r=0.40**

r=0.34**

p=0.000

p=0.001

p=0.001

p=0.022

p=0.000

p=0.000

r=-0.13

r=-0.29**

r=0.25**

r=-0.02

r=0.20**

r=0.20**

p=0.067

p=0.000

p=0.001

p=0.081

p=0.005

p=0.006

r=-0.33**

r=-0.28**

r=0.24**

r=0.18*

r=0.26**

r=0.29**

p=0.000

p=0.000

p=0.001

p=0.013

p=0.000

p=0.000

r=-0.41**

r=-0.35**

r=0.28**

r=0.24**

r=0.37**

r=0.35**

p=0.000

p=0.000

p=0.000

p=0.001

p=0.000

p=0.000

Perceived oral health

Perceived dental treatment need

D

r=-0.22**

r=-0.23**

p=0.002

Physical pain

Psychological discomfort

Physical disability

Psychological disability

Social disability

Handicap

Total score * Correlation is significant at the 0.05 level (2-tailed). ** Correlation is significant at the 0.01 level (2-tailed).

DISCUSSION The aim of this study was to obtain a Romanian version of the OHIP-14 questionnaire that is linguistically and culturally adapted, while preserving the internal consistency and reliability of the original English version. The Romanian version was obtained through the back-translation technique. It was first tested in a pilot study and then on a population of Romanian adults. The results of the study show a very good internal consistency with a Cronbach alpha coefficient of 0.88. This value is consistent with several recommendations: it is higher than the 0.8 suggested as a minimum value for basic research by Nunnally (1978), Carmines and Zeller (1979) and Clark and Watson (1995); given the length of the scale, with 14 items, and the number of participants (187), the alpha coefficient is between 0.7 and 0.9 as Ponterotto and Ruckdeschel suggested

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in 2007. Its value is the same as the one Slade obtained in the original English version in 1997, lower than the ones calculated for the validation of the Swedish (Larsson et al, 2004), Czech (Hodacova et al, 2010), Greek (Papagiannopoulou et al, 2012) and Spanish (Monterro-Martin et al, 2009) versions and higher than the alpha value for the Persian version (Navabi et al, 2010). The Cronbach alpha coefficient has lower values when one of the items is excluded from the analysis. In this study, inter-item correlations were positive, showed homogeneity, and none were high enough to suggest redundancy. The item-total correlations were all above 0.2, which is the minimum value suggested by Kline (1986) for including an item in a scale. Similar results were obtained during the Spanish, Greek and Czech validation of the OHIP-14. The alpha coefficient and the item analysis prove that the internal consistency of the original version was not lost through translation.

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There was a statistically significant correlation between the perceived oral health, the need for dental treatment and the scores of the tested version of the OHIP-14, supporting the convergent validity of the Romanian version. Similar correlations were found by Monterro-Martin et al (2009) and Papagiannopoulou et al (2012). Furthermore, the mean scores of the OHIP-14 were higher, i.e. the quality of life was lower, for respondents showing oral health problems when compared with scores of respondents with no oral health problems. This, in turn, proves the construct validity of the Romanian version of the questionnaire. Physical pain and psychological disability had the strongest impact on the overall OHIP-14 score in this study. This result is similar to that obtained in the Czech study (Hodacova et al, 2010), which reported physical pain as the main contributor to lower quality of life. At the same time, a Romanian study (Murariu and Hanganu, 2009) conducted on adults in Iasi reported physical disability and physical pain as being the subdomains with the strongest impact on the OHIP-14 score. Both Romanian studies concluded that physical pain has a great influence on the quality of life among Romanian adults. Different results were reported by the Spanish (Monterro-Martin et al, 2009) and Greek (Papagiannopoulou et al, 2012) studies, in which the subdomains psychological discomfort and functional limitations contributed most to lower oral healthrelated quality of life. Almost 83% of the respondents in this study were patients under treatment with haemodialysis and 17% were adults attending a dental practice in Bucharest. Due to the wide access to medical procedures and treatments available, including haemodialysis, within the Romanian National Health System, the sample of respondents, although not randomly selected, can be considered valid and representative for the general population. The OHIP-14 was successfully used on a population of haemodialysis patients by Guzeldemir et al (2009), proving to be a sensitive instrument for measuring oral health-related quality of life. Therefore, the fact that most of our respondents suffered from a chronic illness did not have a negative influence on the outcome of this study, namely on the linguistic and cultural validation of the OHIP-14. Although 15% of the studied population came from a rural area, this percentage is not representative of the entire population of Romania. The October 2011 census found that 47% of the Romanian total population live in a rural area (Romanian Na-

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tional Institute of Statistics, 2012). Therefore, we consider that this Romanian form of the questionnaire can be safely administered to people living in urban areas and that it should be used with caution in rural areas. Further testing is needed to prove its validity for use on people from a rural environment. The sample size and the cross-sectional design of this study, although suited for the linguistic and cultural validation, is not sufficient to make an indepth analysis of the impact of oral conditions on quality of life. Further studies, such as longitudinal or case-control studies conducted on larger samples of respondents, are required in the future.

CONCLUSION The results of the present study show that the tested Romanian version of the OHIP-14 has good internal reliability and validity. Furthermore, the characteristics of the original questionnaire were not lost through translation and cultural adaptation. Therefore, we conclude that the Romanian version of the OHIP-14 is a reliable instrument to be used in future studies by other scientists for Romanian people in Romania or abroad.

ACKNOWLEDGEMENTS This study was partially supported by the Sectorial Operational Programme for Human Resources Development, financed by the European Social Fund and by the Romanian Government under the contract number POSDRU/89/1.5/S/64331.

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