APA (7e ed.) Bronvermelding

Gaddum, L. W., & Knowles, H. L. (1953). Our physical environment: A problem approach. University of Florida.

Chicago (17e ed.) Bronvermelding

Gaddum, Leonard W., en Harold L. Knowles. Our Physical Environment: A Problem Approach. Boston, Mass.: University of Florida, 1953.

MLA (9e ed.) Bronvermelding

Gaddum, Leonard W., en Harold L. Knowles. Our Physical Environment: A Problem Approach. University of Florida, 1953.