edited by David E. Long and Bernard Reich
Westview Press, 2002
Buku Teks SO
edited by David E. Long and Bernard Reich
Westview Press, 1986
Buku Teks SO
Palmer, Monte
Thomson Wadsworth, 2007
Buku Teks SO
Bill, James A.
Littel Brown and Company, 1984
Buku Teks
Bill, James A.
Little, Brown, 1979
Buku Teks SO