Paper  bibtex   

@book{felt_mechanical_1916,
	title = {Mechanical arithmetic, or {The} history of the counting machine},
	url = {http://archive.org/details/mechanicalarithm00feltrich},
	language = {eng},
	urldate = {2017-12-16},
	publisher = {[Chicago, Washington Institute},
	author = {Felt, D. E. (Dorr Eugene)},
	collaborator = {{University of California Libraries}},
	year = {1916},
}