APA (7th ed.) Citation

Knowles, M. S. (1979). The adult learner: A neglected species (2. ed.). Gulf Publ.

Chicago Style (17th ed.) Citation

Knowles, Malcolm S. The Adult Learner: A Neglected Species. 2. ed. Houston, Tex. [u.a.]: Gulf Publ, 1979.

MLA (9th ed.) Citation

Knowles, Malcolm S. The Adult Learner: A Neglected Species. 2. ed. Gulf Publ, 1979.