Hans BURUM Raade Ostfold; son Jens born 1715

I have trace my line in the parish registers back to Hans Burum from Raade, Ostfold, Norway. His son was Jens Hansen born 1715. Jens married Marie Nelsdatter. I have seen indications on the LDS sight that Hans was Andersen, but can't figure where they got this. Of course the records are hard to read so..... What other records might be available and how can i continue to trace back further? I have heard there is a book that lists farm names and families. Where can i find this? Thanks for any help or advice you can give. Brian