Digital techniques have created new and stimulating conditions to provide visually impaired people with a better access to written information. The Helene Server project, started in 2000 by BrailleNet, aims at creating technical solutions to help transcribers to rationalize adapted documents production in France. The first action performed was to create a national repository of adapted documents available to transcription centers. In two years, this repository has gathered more than 1.500 books provided by publishers or transcribers. But the great variety of digital formats used by transcribers now raises the problem of resources normalization. This article presents a production chain of accessible documents based on the dtbook XML format.