@book{30566,
	author = {Walsh, William David},
	title = {The diffusion of technological change in the Pennsylvania pig iron industry, 1850-1870},
	publisher = {Arno Press},
	year = {1975, c1967.},
	series = {Dissertations in American economic history},
	address = {New York},
	note = {Originally presented as the author's thesis, Yale, 1967.}
}