temps (durée) (2) stratification (2) sociologie (2) recherche (2) revenu (2) analyse (2) éducation (2) ordre (2) Education (2) Economic conditions (2) Causes (2) Article (2) Death (2) Surveys (2) Social stratification (2) Weights and measures (2) Time (2) Surveys (2) Sociology (2) Socioeconomic status (2) Social status (2) Social mobility (2) Research (2) Order (2) Measurement (2) Income (2) Grammar, Comparative and general--Article (2) Equality (2) Education (2) Death (2)