Staley, Eugene, author
Harper & Brother , 1954
Buku Teks
Bruch, Mathias, author
Westview Press, 1984
Buku Teks
edited by Norman N. Barish and Michel Verhulst
Pergamon Press , 1965
Buku Teks
Avramovic, Dragoslav, author
John Hopkins Press, 1972
Buku Teks
United Nations , 1993
Buku Teks