Sampson, George, author
University Press, 1959
Buku Teks
Sampson, George, author
Cambridge University Press, 1972.
Buku Teks
Burns, E. Bradford, author
Prentice-Hall, 1977
Buku Teks
James E Davis, colsultan
Graphic Learning,, 1978
Buku Referensi
Buku Teks