6 books
Second Annual Report of the Commissioner of Labor and Industry of the Commonwealth of Pennsylvania, 1915, Vol. 2 (Classic Reprint)
Monthly Bulletin of the Pennsylvania Department of Labor and Industry, Vol. 1: A Bulletin of Information for the Public, November, 1914 (Classic Reprint)
Bulletin of the Pennsylvania Department of Labor and Industry, a Bulletin of Information for the Public, Volume V. Series of 1918. No. 1
Alternating Currents and Alternating Current Machinery
Alternating currents and alternating current machinery Volume 2
Alternating Currents and Alternating Current Machinery; Being Volume II of the Text-Book on Electromagnetism and the Construction of Dynamos