Physiological and cellular studies of nitrogen cycling in poplar. 1996. Wetzel, S.; Beardmore, T.; Burgess, D.M.; Sennerby-Forsse, L. Pages 85-90 in J. Karau, compiler. Proceedings of the Canadian Energy Plantation Workshop, May 2-4, 1995, Ganoque, Ontario. Natural Resources Canada, Canadian Forest Service, Headquarters, Ottawa.
Storage compounds in Populus cuttings in response to two different nitrogen regimes. 1995. Wetzel, S.; Sennerby-Forsse, L.; Burgess, D.M. Pages 667-685 in L.O. Nilsson, R.F. Hüttl, and U.T. Johansson, editors. Nutrient Uptake and Cycling in Forest Ecosystems. Kluwer Academic Publishers, Amsterdam, The Netherlands.