APA

Billings E., Westmore A., . (1980). The Billings method: controlling fertility without drugs or devices. New York: Random House.

Chicago

Billings Evelyn, Westmore Ann, . 1980. The Billings method: controlling fertility without drugs or devices. New York: Random House.

Harvard

Billings E., Westmore A., . (1980). The Billings method: controlling fertility without drugs or devices. New York: Random House.

MLA

Billings Evelyn, Westmore Ann, . The Billings method: controlling fertility without drugs or devices. New York: Random House. 1980.