Cita APA

Voelpel, J., & Voelpel, J. (1976). Population programmes and projects. New York, New York: United Nations Fund for Population Activities.

Citación estilo Chicago

Voelpel, Jack, y Jack Voelpel. Population Programmes and Projects. New York, New York: United Nations Fund for Population Activities, 1976.

Cita MLA

Voelpel, Jack, y Jack Voelpel. Population Programmes and Projects. New York, New York: United Nations Fund for Population Activities, 1976.