edited by Gail Elizabeth Wyatt, Gloria Johnson Powell
Sage Publications, 1988
Buku Teks SO
Sage Publications, 1988
Buku Teks
Kelly, Robert L.,author
Wadsworth, 2010
Buku Teks SO
SPAFA, 1984
Buku Referensi
edited by Mari Pritchard Parker, Elvio Angeloni
McGraw-Hill, 2013
Buku Teks SO