Barron's Education Series, Inc. publishes many books on a variety of bird species, including finches.
The Complete Book of Cockatiels
Diane Grindol Howell Book House, 1998.
Let's Celebrate Pet Birds!: How to Understand, Care for and Live Happily With Birds
T.J. Lafeber, DVM Lafeber Co, 1989 (Book is also online at www.lafeber.com)
The Complete Bird Owner's Handbook
Gary A. Gallerstein, DVM (with Heather Acker, AHT) Howell Book House, New York, 1994.
Guide to Pet Birds
Matthew M. Vriends Simon & Schuster, 1984. Fancy Publications publishes the following: