Sapp, G. (1941). Happy helpers. Florida curriculum laboratory, College of education, University of Florida and State dept. of education.
Chicago-referens (17:e uppl.)Sapp, Gertrude. Happy Helpers. Gainesville: Florida curriculum laboratory, College of education, University of Florida and State dept. of education, 1941.
MLA-referens (8:e uppl.)Sapp, Gertrude. Happy Helpers. Florida curriculum laboratory, College of education, University of Florida and State dept. of education, 1941.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.