@book{78350,
	author = {Simonson, Michael R.},
	title = {Teaching and learning at a distance :},
	publisher = {Allyn & Bacon,},
	year = {2009.},
	address = {Boston :},
	edition = {4th ed.},
	url = {http://www.loc.gov/catdir/toc/ecip089/2008003802.html}
}