Ver Steeg, Clarence L.
Harper and Row, 1981
Buku Teks
by Mary Beth Norton. .. [et.al.]
Houghton-Miffiln, 1988
Buku Teks
Brinkley, Alan
McGraw-Hill, 1997
Buku Referensi
Noble, David W
University of minnesota press, 2002
Buku Teks
Todd, Lewis Paul
Harcourt, Brace & World, 1961
Buku Teks