Wadsworth, 1991
Buku Teks
edited by Frank Freidel and Norman Pollack
Rand McNally, 1963
Buku Teks
Adams, James Truslow
1946
Buku Referensi
editor Thomas C. Cochran, Wayne Andrew
Charles Scribner's Sons , 1962
Buku Referensi
U.S. Information Service,, 1981
Buku Teks