Hedge, Tricia
Macmillan, 1985
Buku Teks
Jesness, Jerry, author
Corwin Press, 2004
Buku Teks
Axtell, Roger E.
John Wiley & Sons, 1995
Buku Teks
edited by Harold B. Allen
McGraw-Hill, 1965
Buku Teks
Morgan, John, 1944-2004, author
Cambridge University Press, 1983
Buku Teks