APA (7th ed.) Citation

Knowles, M. S. (1973). The adult learner: A neglected species. Gulf Pub. Co.

Chicago Style (17th ed.) Citation

Knowles, Malcolm Shepherd. The Adult Learner: A Neglected Species. Houston [Tex.]: Gulf Pub. Co, 1973.

MLA (9th ed.) Citation

Knowles, Malcolm Shepherd. The Adult Learner: A Neglected Species. Gulf Pub. Co, 1973.