Kohls, Richard L.
Macmillan, 1971
Buku Teks
Kohls, Richard L.
New York, N.Y. Macmillan c.1972,
Buku Teks
Larson, Adlowe L.
Prentice-Hall, 1957
Buku Teks
Muto, Kazuo
Japan FAO Association , 1987
Buku Teks
Rhodes, V. James
Grid Publishing, Inc, 1978
Buku Teks