@book{21475,
	author = {Clausen, Jens.},
	title = {Experimental studies on the nature of species},
	publisher = {Carnegie Institution,},
	year = {1940-48},
	address = {Washington :},
	note = {Contenio: v.1 Effect of varied environments on western north american plants -- v.2 Plant evolution throught amphiploidyand autoploidy, with... -- v.3 Environmental responses of climatic roces of achillea}
}