@book{60137,
	author = {Beringer, C. and Beringer, J. J.},
	title = {A text-book of assaying},
	publisher = {Project Gutenberg,},
	year = {2006},
	address = {Salt Lake City, UT :},
	note = {Release date is 2006-07-03},
	url = {https://www.gutenberg.org/ebooks/18751}
}