New Light on the History of Correspondence Schools.Published in:Pennsylvania Magazine of History & Biography, 2017, v. 141, n. 3, p. 373, doi. 10.5215/pennmaghistbio.141.3.0373By:HAMPEL, ROBERT L.Publication type:Article
Elevator Education in the Early 20th Century, Part Two.Published in:Elevator World, 2010, v. 58, n. 5, p. 64By:Gray, LeePublication type:Article