Shteppa, Konstantin F., author
Rutgers University Press, 1962
Buku Teks
Shacford, R.H., author
Public Affairs Press, 1952
Buku Teks
The University of Chicago Press, 1983
Buku Teks
Harvard University Press, 1955
Buku Teks
Gallagher, Matthew P., author
Frederick A. Preager, 1963
Buku Teks