@book{201484,
	author = {Varis, Lee. and ebrary, Inc.},
	title = {Mastering exposure and the zone system for digital photographers},
	publisher = {Course Technology PTR,},
	year = {2011.},
	address = {Boston, Mass., U.S.A. :},
	note = {Includes index.},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10400806}
}