Irene Joos ... [and others] ; editor, Widyastuti Palupi
EGC, 2009
Buku Teks
Fairhurst, Michael C., author
UI-Press, 1995
Buku Teks
Djoehariah Koestijah, author
Fakultas Hukum Universitas Indonesia, 1996
UI - Skripsi (Membership)
Sarana Informatika Kelompok Gramedia, 1991
Buku Referensi
Universitas Indonesia, 2013
UI - Skripsi (Membership)