Fink, Arlene, author
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Litwin, Marks
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
SEAMEO, 1997
Buku Teks
Fink, Arlene, author
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Unun Khamida Qodarina, author
Universitas Indonesia, 2014
UI - Skripsi (Membership)