@book{23270,
	author = {Haslam, S. M. and Wolseley, P. A.},
	title = {River plants of western Europe :},
	publisher = {Cambridge University Press,},
	year = {c1987.},
	address = {New York :},
	url = {http://www.loc.gov/catdir/description/cam032/85005962.html}
}