Bunbongkarn, Suchit
Institute of southeast Asian studies, 1996
Buku Teks SO
editors, Marlon A. Wui, MA. Glenda S. Lopez
Third World Studies Center, 1997
Buku Teks
Laquian, Aprodicio A.
University of Philippines, 1966
Buku Teks
Artikel Jurnal
Artikel Jurnal