@book{59671,
	author = {North American Conference on Symbiotic Nitrogen Fixation ( and Graham, P. H.},
	title = {Symbiotic nitrogen fixation},
	publisher = {Kluwer,},
	year = {1994},
	series = {Developments in plant and soil sciences},
	address = {Dordrecht :},
	note = {Artículos aparecidos en : Plant and Soil vol. 161 (1) 1994}
}