Hamilton, C.W.؛ Reichard, S.H. (1992). "Current practice in the use of subspecies, variety, and forma in the classification of wild plants". Taxon. ج. 41 ع. 3: 485–498. DOI:10.2307/1222819. JSTOR:1222819.
Hamilton, C.W.؛ Reichard, S.H. (1992). "Current practice in the use of subspecies, variety, and forma in the classification of wild plants". Taxon. ج. 41 ع. 3: 485–498. DOI:10.2307/1222819. JSTOR:1222819.