Artikel Jurnal
Thomas S. Weinberg, Staci Newmahr, editors
SAGE, 2015
Buku Teks
Miles, Herbert J.
Zondervan Publishing House, 1982
Buku Teks
edited by Susan J. Bunting
McGraw-Hill, 2003
Buku Teks
Siahaan, Melinda, author
Universitas Indonesia, 2003
UI - Tesis (Membership)