The Reader's Digest Association
The Reader`s Digest Association, 1967
Buku Teks SO
Frans M. Parera
Kompas Media Nusantara, 2000
Buku Teks SO
L. Murbandono
Grasindo, 2004
Buku Teks
Irza Arnyta Djafaar
Universitas Indonesia, 1999
UI - Tesis Membership
Narasi, 2006
Buku Teks SO