Reilly, Frank K.
The Dryden Press, 1994
Buku Teks
Wendt, Paul F.
The University of California, 1966
Buku Teks
Dar, Usha
Sterling Publishers Pvt.Ltd., 1979
Buku Teks SO
Curley, Anthony J.
Harper & Row , 1979
Buku Teks SO
Manurung, Apriandi
2017
UI - Skripsi Membership