International Geological Congress : report of the twenty-first session, Norden (Denmark, Finland, Iceland, Norway, Sweden), 1960. - Sorgenfrei, Theodor, 1915-1972; Landergren, Sture Fitz Carlos, 1897-; Sahama, Th. G., 1910-1983 (Det Berlingske Bogtrykkeri, 1960)