Contraception · 1999 · 23 citations · 7 references
MedicineGynecologyObstetricsFertilityReproductive HealthReproductive MedicineDeterminants Of FertilityFertility AwarenessFertility Awareness MethodsFertility EpidemiologyIrregular Menstrual CyclesMenstrual CycleCycle RegularityFertility Awareness Method Effectiveness
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The Length and Variability of the Human Menstrual Cycle
Leonard Chiazze · JAMA · 1968 · 375 citations