Petrographic provinces, igneous and metamorphic rocks : proceedings of the section 13 - Oftedahl, Christoffer (Hrsg.); International Geological Congress (21 : 1960 : Kopenhagen) (Report of the twenty-first session / International Geological Congress : Norden, Denmark, Finland, Iceland, Norway, Sweden 1960 / gen. ed.: Theodor Sorgenfrei, 1960)