C. MAIJER; P. A. M. ANDRIESSEN; E. H. HEBEDA; J. B. H. JANSEN; R.H. VERSCHURE. Osumilite, an approximately 970 Ma old high-temperature index mineral of the granulite-facies metamorphism in Rogaland, SW Norway. Netherlands Journal of Geosciences, p. 267-272, 1 Jan. 1981.