Johnson, Gerry, author
Prentice-Hall, 2002
Buku Teks
Monroe, James Stewart, 1938-, author
Wadsworth, 1997
Buku Teks
Davidson, Jon P., author
Prentice Hall, 1997
Buku Teks
Beekman, George, author
Pretince Hall, 2002
Buku Teks
Smith, Ella Thea, author
Harcourt, Brace & World, 1959
Buku Teks