Kresten Nielsen, J. ., and M. . Pedersen. “Hydrothermal Activity in the Upper Permian Ravnefjeld Formation of Central East Greenland – a Study of Sulphide Morphotypes”. Geology of Greenland Survey Bulletin, vol. 180, Dec. 1998, pp. 81-87, doi:10.34194/ggub.v180.5090.