Drake, Charles D.
Sweet & Maxwell, 1972
Buku Teks
Cremeans, Charles D
Frederck A. Praeger, 1963
Buku Teks SO
Reuschlein, Harold Gill
St. Paul Minn, 1990
Buku Teks
Miller, Charles David, 1942-
Scott, Foresman and Co., 1978
Buku Teks SO
Bonham, Charles D.
John Wiley & Sons, 1989
Buku Teks