@book{12152,
	author = {Krajcik, Joseph S. and Czerniak, Charlene.},
	title = {Teaching children science :},
	publisher = {McGraw-Hill,},
	year = {c1999.},
	address = {Boston :},
	url = {http://www.loc.gov/catdir/description/mh023/98039798.html}
}