@book{28022,
	author = {Tveito, Aslak, and Winther, Ragnar. and ebrary, Inc.},
	title = {Introduction to partial differential equations},
	publisher = {Springer,},
	year = {c1998.},
	series = {Texts in applied mathematics ;},
	address = {New York :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10015670}
}