Universitas Indonesia, 1991
UI - Skripsi (Membership)
Silalahi, Patricia Samantha
2013
UI - Tesis (Membership)
Hausman, Carl
Harper Collins, 1992
Buku Teks
Sitepu, Helen
Universitas Indonesia, 2006
UI - Skripsi (Membership)
Agus Purwanto
Program Pascasarjana Universitas Indonesia, 2005
UI - Tesis (Membership)