Schwartz, Benjamin
Harvard University Press, 1952, 1961
Buku Teks SO
Schwartz, Benjamin
Harper Torchbooks and The Academy Library, 1967
Buku Teks SO
Strong, Anna Louise
New World Press, 1959
Buku Teks SO
War Departement, 1944
Buku Referensi
Singer, P. W.
Cornell University Press, 2003
Buku Teks