linking MARTIN G. NORUM to MARTINUS NORUM

I am attempting to establish the link between my Grandfather in the USA and his Parents and Family in Norway. I have linked my GrFather MARTIN GEORGE NORUM to MARTINUS NORUM and his wife GRETHE thru information at this site. When I try to locate background on them in the Digitalarkivet lists for Census, Parish Registers, Emigrant Rosters, ect. for years earlier than1900, I can not find any possible matches. I have tried to match possible birth dates, Christenings, marriages, Census listings, etc.. I have screened the listings for Nord Trøndelag, Vest Agder, Møre og Romsdal, Levanger, Flekkefjord, Veblungsnes, Grytten, also Alesund, but have had no luck. It appears Martinus and Grethe are my GrGrand Parents and Peter-Pauline and OleNorum Sættenes are their children. MARTINUS = Levanger Nord Trøndelag GRETHE = Flekkefjord, Vest Agder PAULINE = Flekkefjord, Vest Agder OLE = Veblungsnes, Grytten, Møre og Romsdal I have read and re-read the users information, I'm still missing something - can anyone help?