Introduction: some facts and figures.
D003657:Decision Making; D003906:Developing Countries; D004467:Economics; D004522:Educational Status; D004651:Employment; D006262:Health; D008430:Maternal-Child Health Centers; D009747:Nutritional Physiological Phenomena; D009790:Occupations; D012106:Research; D012923:Social Class; D012959:Socioeconomic Factors; D013997:Time Factors