compiled and arranged by Elizabeth Lodor Merchant
Holt, Rinehart and Winston, 1961
Buku Referensi
Chopra, Deepak, author
Harmony Books, 1995
Buku Teks
Gerritsen, WP
Verloren, 1991
Buku Teks
Broecks, J.L
Manteau , 1989
Buku Teks
Brouwers, Jeroen, author
UItgeverij Atlas, 2004
Buku Teks