Newton, J.D., F.A. Wyatt, and A.L. Brown (1945), Effects of cultivation and cropping on the chemical composition of some western Canada prairie soils; Part III, Scientiﬁc Agriculture, 25: 718–737.
Paul, K.I., P.J. Polglase, J.G. Nyakuengama et P.K. Khanna (2002), Change in soil carbon following afforestation, Forest Ecology and Management, 168(1–3): 241–257.