This Norwegian issue celebrated the 150th birthday of Aasmund Olavsson Vinje, poet.
There were two stamps, 50 0re sepia and 65 ore carmine. They were released May 21, 1968. Designed by Knut Lokke-Sorensen and recess printed by the Bank of Norway, on fluorescent paper.
For detailed information on Vinje, see:
http://en.wikipedia.org/wiki/Aasmund_Olavsson_Vinje
If you collect poets on stamps, you should seriously consider joining JAPOS (Journalists, Authors and Poets on Stamps), a highly-respected Unit of the American Topical Association.http://americantopicalassn.org/study_units/journalistsauthorsunit.html