Petrography of a group of alkali-trachytic dyke rocks from the Julianehaab district, South Greenland A contribution to the alkali feldspar problem by J. Bondam. The mesozoic sediments of Qeqertarssuaq, Umanak district, West Greenland. By Hilmar Ødum and Eske Koch - Bondam, J. (Meddelelser om Grønland, 1955)