Knoll, Robert E., author
Harcourt, Brace and Company, 1959
Buku Teks
Nilsen, Don L. F.
Regents Publishing, 1973
Buku Teks
Stewart, Rosemary, author
McGraw-Hill, 1976
Buku Teks
edited by Benjamin B. Hoover, Donald S. Taylor
Holt, 1957
Buku Teks
Blair, Walter, author
Scott, Foresman and Company, 1949
Buku Teks