@book{969,
	author = {Billstein, Rick. and Libeskind, Shlomo.},
	title = {A problem solving approach to mathematics for elementary school teachers /},
	publisher = {Addison-Wesley,},
	year = {c2010.},
	address = {Boston :},
	edition = {10th ed.},
	url = {http://www.loc.gov/catdir/toc/ecip0827/2008039186.html}
}