Sophian Syah, author
Fakultas Hukum Universitas Indonesia, 2006
UI - Tesis Membership
Panca Usaha, 2000
Buku Referensi
Harahap, Harief, author
Pradnya Paramita, 1977
Buku Teks
Saragih, Djaren, author
Tarsito, 1980
Buku Teks
Harahap, Harief, author
Isabella Brothers, 1973
Buku Teks