@book{84137,
	author = {Checkley, Kathy. and ebrary, Inc.},
	title = {The essentials of mathematics, grades 7-12},
	publisher = {Association for Supervision and Curriculum Development,},
	year = {c2006.},
	series = {Priorities in practice},
	address = {Alexandria, VA :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10141220}
}