Levin, Jonathan L.
Institute Finance, 1991
Buku Referensi
Morrow, Keith
The Royal Society of Arts, 1977
Buku Teks SO
edited by Ann Schmidt Luggen
Mosby Year Book, 1996
Buku Teks SO
Zaidan Fajar Nurmansyah
Fakultas Ilmu Administrasi. Universitas Indonesia, 2020
UI - Skripsi Membership
Bacal, Robert
McGraw-Hill , 2004
Buku Teks