Link, Arthur S., author
Alfreda A. Knopf, 1963
Buku Teks
Dulles, Foster Rhea, author
Houghton-Mifflin, 1945
Buku Teks
Levy, John M., author
Pearson Education International, 2009
Buku Teks
Levy, John M., author
Routledge, 2013
Buku Teks
Levy, John M., author
Prentice-Hall, 1991
Buku Referensi