Cita APA (7a ed.)

Willke, J., & Willke, B. (1990). Abortion: Questions & answers. Hayes Publishing Company.

Cita Chicago Style (17a ed.)

Willke, Jack, y Barbara Willke. Abortion: Questions & Answers. Cincinnati: Hayes Publishing Company, 1990.

Cita MLA (9a ed.)

Willke, Jack, y Barbara Willke. Abortion: Questions & Answers. Hayes Publishing Company, 1990.