Siagian, Sondang P., author
Bumi Aksara , 1996
Buku Teks
Siagian, Sondang P., author
Bina Aksara, 1988
Buku Teks
Cummings, Paul W., author
Pustaka Binaman Pressindo, 1984
Buku Teks
Cummings, Paul W., author
PPM, 1984
Buku Teks
Ahmad Fadil, author
Universitas Indonesia, 1998
UI - Tesis (Membership)