@book{73490,
	author = {Labriola, Antonio, and Kerr, Charles H.,},
	title = {Essays on the Materialistic Conception of History},
	publisher = {Project Gutenberg,},
	year = {2010},
	address = {Salt Lake City, UT :},
	note = {Release date is 2010-06-01},
	url = {https://www.gutenberg.org/ebooks/32644}
}