Dr. KristjÃ n EldjÃ rn ( December 6 , 1916 â `` September 14 , 1982 ) was the 3rd president of Iceland . He was president from 1968 to 1980 . Dr. KristjÃ n EldjÃ rn ( 6 December 1916 â `` 14 September 1982 ) was the third President of Iceland , from 1968 to 1980 .