The most helpful has been the Digital Archives of Norway at
www.hist.uib.no/arkivverket/index-en.htmLeft mouse on the source categories or municipalities at the time of source will offerquite a lot of information. I have some other sites which could be helpful. If you could include an E-mail address it would be helpful I could simply attach web site addresses as opposed writing them out. Good luck and I hope you find what you are looking for.