Wishik, S. M., & Helbig, D. W. (1972). The fertility pattern method: Estimation of fertility change by retrospective quasi-cohort analysis of group specific fertility patterns. Colombia University.
Chicago-referens (17:e uppl.)Wishik, Samuel M., och Donald W. Helbig. The Fertility Pattern Method: Estimation of Fertility Change by Retrospective Quasi-cohort Analysis of Group Specific Fertility Patterns. New York: Colombia University, 1972.
MLA-referens (9:e uppl.)Wishik, Samuel M., och Donald W. Helbig. The Fertility Pattern Method: Estimation of Fertility Change by Retrospective Quasi-cohort Analysis of Group Specific Fertility Patterns. Colombia University, 1972.
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