@book{30120,
	author = {Copi, Irving M., and Beard, Robert W.,},
	title = {Essays on Wittgenstein's Tractatus /},
	publisher = {Hafner Press,},
	year = {c1966.},
	address = {New York :},
	note = {Reprint of the ed. published by Macmillan, New York.}
}