Nobbs, Jack
Macmillan Education, 1989
Buku Teks SO
Finsterbusch, Kurt
McGraw-Hill, 2006
Buku Teks SO
Kurt Finsterbusch, editor
McGraw-Hill, 2007
Buku Teks SO
Fulcher, James
Oxford University Press, 2007
Buku Teks SO
Macionis, John J.
Prentice-Hall, 2008
Buku Teks SO