Kalijarvi, Thorsten V.
Thomas Y. Crowell, 1954
Buku Teks SO
Organski, A.F.K.
Alfred A. Knopf, 1969
Buku Teks SO
Rostow, Walt Whitman
A Clarion Book, 1969
Buku Teks SO
Mander, Linden A.
Stanford University Press, 1948
Buku Teks
edited by Roy C. Macridis
Prentice-Hall, 1967
Buku Teks SO