Strategic Direction Publishers, [date of publication not identified]
Buku Referensi
Artikel Jurnal
Caplen, Rowland
Business Books , 1975
Buku Teks
Hansen, Bertrand L., author
Prentice-Hall, 1966
Buku Teks
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 1997
UI - Skripsi (Membership)