Krupp

Edna Fay Campbell, Victor L. Webb & William L. Nida.  The Old World Past and Present.  Chicago:  Scott, Foresman & Co., 1942.  A revision of the 1937 edition.

Krupp Reinhausen, 1950's.  From.  F. Roy Willis.  Western Civilization.  An Urban Perspective.  Volume III.  D.C. Heath & Co., 1973.