@article {48650,
	title = {Effects of N, NP, and NPKS fertilizers applied to four-year old hybrid poplar plantations},
	volume = {35},
	year = {2008},
	pages = {221-233},
	publisher = {New Forests},
	url = {http://www.springerlink.com/content/fk34280241862g68/fulltext.pdf},
	author = {van den Driessche, R. and Thomas, Barbara R. and Kamelchuk, David P.}
}
