Simbolon, Rio B. Purba
Fakultas Teknik Universitas Indonesia, 1998
UI - Skripsi (Membership)
Amstrongmia
2000
UI - Skripsi (Membership)
Knox, Frank M.
McGraw-Hill, 1952
Buku Teks
Hall, Rodney
University of Queensland Press, 1978
Buku Teks
Herman Burhanuddin
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2001
UI - Tesis (Membership)