@book{68477,
	author = {Ovchinnikov, S. G. and Val�kov, V. V. and ebrary, Inc.},
	title = {Hubbard operators in the theory of strongly correlated electrons},
	publisher = {Imperial College Press,},
	year = {c2004.},
	address = {London :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10088384}
}