Weinberg, Meyer
Prentice Hall Inc., 1965
Buku Teks
Clark, Wilfrid E. Le Gros, author
Quadrangle Books, 1971
Buku Teks
Clark, Wilfrid E. Le Gros, author
Quadrangle Books, 1971
Buku Teks
Plamenatz, John
Longman, 1991
Buku Teks
Maritain, Jacques
The University of Chicago Press, 1951
Buku Teks