Laurel Saville, Steve Gordhan, Jodhua Berger, Sarch Dougher, editor
Page one publishing pte ltd, 2011
Buku Referensi
Thompson, Willard M.
McGraw-Hill , 1968
Buku Teks
Donatelle, Rebecca J.
Allyn and Bacon , 1997
Buku Teks
Macionis, John J.
Prentice-Hall, 2000
Buku Teks
Chandler, Daniel
Routledge, 2002
Buku Teks