Kintner, Earl W.
Macmillan Publishing Co.Inc., 1973
Buku Teks
Purdy, Harry Leslie, author
Prentice-Hall, 1942
Buku Teks
Wolfe, Arthur D., author
John Wiley & Sons, 1984
Buku Teks
Doris, Lillian
Prentice-Hall, 1951
Buku Teks
Little, Brown , 1980
Buku Teks