APA (7e ed.) Bronvermelding

Sapp, G. (1941). Happy helpers. Florida curriculum laboratory, College of education, University of Florida and State dept. of education.

Chicago (17e ed.) Bronvermelding

Sapp, Gertrude. Happy Helpers. Gainesville: Florida curriculum laboratory, College of education, University of Florida and State dept. of education, 1941.

MLA (8e ed.) Bronvermelding

Sapp, Gertrude. Happy Helpers. Florida curriculum laboratory, College of education, University of Florida and State dept. of education, 1941.