edited by Ray Woolfe, Windy Dryden, Sheelagh Strawbridge
Sage Publications, 2003
Buku Referensi
Colin Lago, editor
McGraw-Hill, 2011
Buku Teks SO
edited by James G. March
Rand McNally, 1965
Buku Teks
Maggie Robson; Sue Pattison, editor
Sage, 2018
Buku Teks SO
Shim, Jae K.
Prentice-Hall, 1996
Buku Referensi