Pickett, K.H. Spencer
John Wiley & Sons, 2005
Buku Referensi
Pickett, K.H. Spencer
John Wiley & Sons, 2005
Buku Teks
Brink, Victor Z.
The Ronald Press, 1958
Buku Teks
Njoedarwini Soekanto
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 1980
UI - Skripsi (Membership)
Shont, Esther M.
John Wiley & Sons, 1980
Buku Teks