Cita APA (7th ed.)

Kippley, J. F., & Kippley, S. (1979). The art of natural family planning. Couple to couple League.

Cita Chicago (17th ed.)

Kippley, John F., i Sheila Kippley. The Art of Natural Family Planning. Cincinnati: Couple to couple League, 1979.

Cita MLA (9th ed.)

Kippley, John F., i Sheila Kippley. The Art of Natural Family Planning. Couple to couple League, 1979.