Cita APA (7a ed.)

Garrison, D. R. (1997). Self-directed learning: Toward a comprehensive model. [s.n.].

Cita Chicago Style (17a ed.)

Garrison, D. R. Self-directed Learning: Toward a Comprehensive Model. [S.l.]: [s.n.], 1997.

Cita MLA (9a ed.)

Garrison, D. R. Self-directed Learning: Toward a Comprehensive Model. [s.n.], 1997.