Alden, John Richard, author
Harper & Row Publishers, 1963
Buku Teks
Adams, James Truslow, author
1946
Buku Referensi
editor Thomas C. Cochran, Wayne Andrew
Charles Scribner's Sons , 1962
Buku Referensi
editor, Gorton Carruth
Thomas Y. Growell, 1962
Buku Referensi
U.S. Information Service,, 1981
Buku Teks