What is natural fertility?  The modelling of a concept.
Wilson
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C
Oeppen
J
J
Pardoe
M
M
D000367:Age Factors; D001695:Biology; D001723:Birth Rate; D003625:Data Collection; D003710:Demography; D004194:Disease; D004467:Economics; D005069:Evaluation Studies as Topic; D005298:Fertility; D007246:Infertility; D008423:Maternal Age; D008722:Methods; D008962:Models, Theoretical; D010827:Physiology; D011153:Population; D011154:Population Characteristics; D011157:Population Dynamics; D012098:Reproduction; D012106:Research; D012107:Research Design; D012959:Socioeconomic Factors; D013223:Statistics as Topic; D014566:Urogenital System
Age Factors; Age Specific Fertility Rate; Biology; Birth Rate; Critique; Data Collection; Data Sources; Demographic Analysis; Demographic Factors; Differential Fertility; Diseases; Economic Factors; Estimation Technics; Evaluation; Fertility; Fertility Measurements; Fertility Rate; Infertility; Marital Fertility; Measurement; Methodological Studies; Models, Theoretical; Natural Fertility--determinants; Physiology; Population; Population Characteristics; Population Dynamics; Reproduction; Research Methodology; Socioeconomic Factors; Urogenital Effects; Urogenital System; World