Crawford, William R., author
Frederick A. Praeger, 1961
Buku Teks
Wynia, Gary W., author
Cambridge University Press , 1984
Buku Teks
Martin, Michael Rheta, author
The Bobbs Merrill, 1968
Buku Referensi
Wilgus, A. Curtis, author
Barner & Noble, 1963
Buku Teks
Ronning, C. Neale
Martinus Nijhoff, 1965
Buku Teks