I have been trying to research this man as well as a few others from the 15th century, but would like to get a grasp for their personal beliefs, not simply by what others have said of them, but what they've said themselves. He has apparently written several books, so I'm sure there must be a place of the internet for such an archive or at least a place I could get a hard copy of his works. Is there a particular site that could be of assistance? I have had no luck.