by Harry Emerson Fosdick., Includes indexes., Main Heritage Shelves General, DS107.3 .F67 1930, Book, Item-ID: i10042611, BIB-ID: 1006064, Includes bibliographical references (p. 295-297).
by Charles J. Rosebault., Maps on lining-papers., Main Heritage Shelves General, D198.4.S2 R67 1930, Book, Item-ID: i10173432, BIB-ID: 1018979, "Principal sources": p. 305.