Working with Others: Accessibility and User Research
http://www.alistapart.com/articles/workingwithothers

Boscarol, Maurizio
List Apart, A
2006

Abstract:

After personally observing users with disabilities interacting with websites in unexpected ways, I have come to believe strongly in the value of user research--and to suspect that we really don't know quite as much about real-world accessibility as we think we do.