Sørensen, H. M., and Ole V. Petersen. “On the Mineralogy and Paragenesis of Tugtupite Na8Al2Be2Si8O24(Cl, S)2”. Meddelelser om Grønland 181, no. 13 (June 30, 1971): 57 pp. Accessed December 28, 2025. https://tidsskrift.dk/meddrgroenland/article/view/153142.