Winterowd, W. Ross
Holt, Rinehart and Winston, 1968
Buku Teks
Winterowd, W. Ross
Harcourt Brace Jovanovich, 1981
Buku Teks
Connolly, Francis
Harcourt, Brace & World, 1969
Buku Teks
Tibbetts, A.M.
Scott, Foresman and Company, 1979
Buku Teks
Brown, Bruce
Dickenson, 1969
Buku Teks