Billings, E., & Westmore, A. (1980). The Billings method of Natural Family Planning: Controlling fertility without drugs or devices (1st American ed.). Random House.
Style de citation Chicago (17e éd.)Billings, Evelyn, et Ann Westmore. The Billings Method of Natural Family Planning: Controlling Fertility Without Drugs or Devices. 1st American ed. New York: Random House, 1980.
Style de citation MLA (8e éd.)Billings, Evelyn, et Ann Westmore. The Billings Method of Natural Family Planning: Controlling Fertility Without Drugs or Devices. 1st American ed. Random House, 1980.
Attention : ces citations peuvent ne pas être correctes à 100%.