Budi Waluyo
Universitas Indonesia, 2003
UI - Tesis Membership
Dian Dwi Laksani
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2009
UI - Tesis Open
Carnes, W. Stansbury
HarperBusiness, 1992
Buku Referensi
Biro Pusat Statistik, 1983
Buku Teks
Andrea Burgess [and 10 others]
Profile Books Ltd, 2019
Buku Teks SO