Cita APA (7a ed.)

Biddle, S., & Smith, R. A. (1991). Motivating adults for physical activity: Towards a healthier present. [s.n.].

Cita Chicago Style (17a ed.)

Biddle, Stuart, y R. Andrew Smith. Motivating Adults for Physical Activity: Towards a Healthier Present. [S.l.]: [s.n.], 1991.

Cita MLA (9a ed.)

Biddle, Stuart, y R. Andrew Smith. Motivating Adults for Physical Activity: Towards a Healthier Present. [s.n.], 1991.