Voice of America Forum Lectures, 1967
Buku Teks
Wadsworth, 1991
Buku Teks
edited by Frank Freidel and Norman Pollack
Rand McNally, 1963
Buku Teks
Adams, James Truslow, author
1946
Buku Referensi
editor Thomas C. Cochran, Wayne Andrew
Charles Scribner's Sons , 1962
Buku Referensi