How to Avoid Screen Reader 'Noise Pollution'
http://www.dmeurope.com/default.asp?ArticleID=7222

Moss, Trenton
Digital Media Europe
2005

Abstract:

Surely there can't be a skill to writing ALT text for images? You just pop a description in there and you're good to go, right? Well, kind of. Sure, it's not rocket science, but there are a few guidelines you need to follow.