@book{176493,
	author = {Singer, Dorothy G. and Singer, Jerome L. and ebrary, Inc.},
	title = {Imagination and play in the electronic age},
	publisher = {Harvard University Press,},
	year = {2005.},
	address = {Cambridge, MA :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10312749}
}