Não informado. (1937). Agricultural Education. American Vocational Association, Agricultural Section.
Chicago-referens (17:e uppl.)Não informado. Agricultural Education. Des Moines, Iowa: American Vocational Association, Agricultural Section, 1937.
MLA-referens (8:e uppl.)Não informado. Agricultural Education. American Vocational Association, Agricultural Section, 1937.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.