Omar, Ogenyi
Financial times, 1999
Buku Teks
Taller, Terry, author
McGraw-Hill Ryerson, 1977
Buku Teks
Jones, Fred M.
Richard D. Irwin , 1957
Buku Teks
Jeffry Andreas, author
Fakultas Ekonomi dan Bisinis Universitas Indonesia, 2021
UI - Skripsi (Membership)
Warren G. Meyer [and others]
Elex Media Komputindo, 1992
Buku Teks