There are several contemporary books written by the chronicler William (Guillaume ) de Jumeige, a Benedictine monk. They discuss all the major families of Normandy. You should easily find them at Archive.net. You may have to join ( at no cost ) in order to search the texts themselves. If not send me an e-mail. I shall give you a hand. some are written in Latin and French so may require translation service. His writings are considered to be the most reliable sources.