Grogan, Ewart Scott, 1874-1967-, Russell E. Train Africana Collection (Smithsonian Libraries) DSI · Washington, D.C. : Government Printing Office · leaf 23
Smithsonian Report, 1900. — Grogai Plate I The Volcanoes from Lake Kivu. View from Southeast. … The Volcanoes Mount Gotzen and Mount Sharp, from the Northeast.
Africa -- Description and travel
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
