Iowa State College. Agricultural Extension Dept & Iowa State College. Agricultural Extension Dept. Schools Section. (1912). School circular. Dept. of Agricultural Extension, Schools Section.
Chicago-referens (17:e uppl.)Iowa State College. Agricultural Extension Dept och Iowa State College. Agricultural Extension Dept. Schools Section. School Circular. Ames, Iowa: Dept. of Agricultural Extension, Schools Section, 1912.
MLA-referens (8:e uppl.)Iowa State College. Agricultural Extension Dept och Iowa State College. Agricultural Extension Dept. Schools Section. School Circular. Dept. of Agricultural Extension, Schools Section, 1912.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.