Citation: Groat, L. A.; Raudsepp, M.; Hawthorne, F. C.; Ercit, T. S.; Sherriff, B. L.; Hartman, J. S. (1990). The amblygonite-montebrasite series: Characterization by single-crystal structure refinement, infrared spectroscopy and multinuclear MAS-NMR spectroscopy sample M6116. American Mineralogist, 75, pp. 992-1008.