@book{72005,
	author = {Clark, John Bates,},
	title = {Essentials of Economic Theory :},
	publisher = {Project Gutenberg,},
	year = {2010},
	address = {Salt Lake City, UT :},
	note = {Release date is 2010-02-02},
	url = {https://www.gutenberg.org/ebooks/31159}
}