Frison-Roche, Roger
Bruxelles Zurich Monreal, 1981
Buku Teks
The Reader's Digest Association, 1988
Buku Referensi
Readers Digest, 1985
Buku Referensi
Sonya Angraini, author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2007
UI - Skripsi (Membership)
Reader's Digest Association.
Reader's Digest Association, 1968
Buku Referensi