puits (1) enquête (1) établissement scolaire (1) échantillonnage (1) région (1) surveillance (1) soins de santé (1) santé (1) champ (1) âge (1) comparaison (1) enfant (1) Monitoring (1) Language (1) Comparison (1) Selection (1) Methods (1) Identification (1) Teenagers (1) Students (1) Standards (1) School children (1) Sampling (1) Questionnaires (1) Medical care (1) Human beings (1) Lifestyles (1) Language and languages (1) Identification (1) Health surveys (1)