APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

Knowles, Malcolm Shepherd. The Adult Learner: A Neglected Species. 4th ed. Houston: Gulf Pub. Co, 1990.

MLA (9th ed.) Citation

Knowles, Malcolm Shepherd. The Adult Learner: A Neglected Species. 4th ed. Gulf Pub. Co, 1990.