@book{30574,
	author = {Swartz, Clifford E. and ebrary, Inc.},
	title = {Back-of-the-envelope physics},
	publisher = {Johns Hopkins University Press,},
	year = {2003.},
	address = {Baltimore :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10070257}
}