Sinaga, Reynhard Tambos Maruli Tua, author
Fakultas Teknik Universitas Indonesia, 2006
UI - Skripsi (Membership)
edited by Magie Toy
Academy Editions, 1995
Buku Teks
Vale, Lawrence J., author
Routledge, 2008
Buku Teks
edited by Andrew Ballantyne
Routledge, 2010
Buku Teks
Conway, Hazel, author
Routledge , 1994
Buku Teks