Timasheff, Nicholas S., author
Random House, 1961
Buku Teks
Kelsen, Hans, author
Kegan Paul : Trench : Trubner , 1946
Buku Teks
Hoselitz, Bert F., author
Free Press of Glencoe, 1960
Buku Teks
Von Grunebaum, G.E. (Gustave Edmund), 1909-1972
Routledge & Kegan Paul, 1955
Buku Teks
Hilberseimer, Ludwig
Paul Theobald & Co. , 1955
Buku Teks