Census help....again...

Could someone please help me with getting links to census records proir to 1900..I am looking for earlier records for Kristian Martinsen and Mathea Olsen and their children. They were in Vardal on the 1900 census, but I am interested in earlier records, mainly to verify all their children. Thanks for your time and help. I really appreciate it!!!! P.S. I am also interested in ANY information on the family that you might find..thanks!!!!