Williams, J. T. 1. (1968). The nitrogen relations and other ecological investigations on wet fertilised meadows. Buchdruckerei.
Chicago-referens (17:e uppl.)Williams, John Trevor 1938. The Nitrogen Relations and Other Ecological Investigations on Wet Fertilised Meadows. Zurich: Buchdruckerei, 1968.
MLA-referens (9:e uppl.)Williams, John Trevor 1938. The Nitrogen Relations and Other Ecological Investigations on Wet Fertilised Meadows. Buchdruckerei, 1968.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.