APA (7th ed.) Citation

Knowles, M. S. (1990). The adult learner: A neglected species (4. ed.). Gulf Publ. Co.

Chicago Style (17th ed.) Citation

Knowles, Malcolm S. The Adult Learner: A Neglected Species. 4. ed. Houston u.a: Gulf Publ. Co, 1990.

MLA (9th ed.) Citation

Knowles, Malcolm S. The Adult Learner: A Neglected Species. 4. ed. Gulf Publ. Co, 1990.