Não informado. (1913). Journal of agricultural research. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Journal of Agricultural Research. Washington: U.S. Department of Agriculture, 1913.
MLA-referens (8:e uppl.)Não informado. Journal of Agricultural Research. U.S. Department of Agriculture, 1913.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.