Bursk, Edward Collins, author
Cambridge, Mass, Harvard University Press
Buku Teks
Hicks, Herbert G., author
McGraw-Hill Kogakusha, 1974
Buku Teks
Sampson, Robert C., author
McGraw-Hill , 1965
Buku Teks
Turner, Wayne C., author
Prentice-Hall, 1978
Buku Teks
Rice, A K
Tavistock Publications, 1963
Buku Teks