Stewart, Oscar M.
Ginn and Co., 1957
Buku Teks
Kane, Joseph W., 1938-, author
John Wiley & Sons, 1983
Buku Teks
California Research and Education Association, 1995
Buku Teks
Leon, M.
Academic Press , 1973
Buku Teks
Nelkon, M.
Heineman Educational, 1962
Buku Teks