Cita APA

(1986). The Billings method: A method of natural family planning. Mandeville, L.A.: Family of the Americas Foundations.

Citación estilo Chicago

The Billings Method: A Method of Natural Family Planning. Mandeville, L.A.: Family of the Americas Foundations, 1986.

Cita MLA

The Billings Method: A Method of Natural Family Planning. Mandeville, L.A.: Family of the Americas Foundations, 1986.