Illinois Natural History Survey. (2001). Biological notes. Natural History Survey Division.
Citação do estilo Chicago (17ª ed.)Illinois Natural History Survey. Biological Notes. Urbana, Ill: Natural History Survey Division, 2001.
Citação MLA (8ª ed.)Illinois Natural History Survey. Biological Notes. Natural History Survey Division, 2001.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.