Coba jelasin Lihat pula dari Keluarga berencana alami dong

Ajaran Katolik mengenai moralitas seksual

Moral Use of Natural Family Planning  (PDF). Prof. Janet E. Smith (Moral Theologian and Public Speaker). B.A., M.A., Ph.D., School of Theology, Fr. Michael J. McGivney Chair in Life Ethics, Professor of Moral Theology. At SHMS 2001–present.