J. Theo Kloprogge, Huada Ruan, Loc V. Duong and Ray L. Frost 2001. FT-IR and Raman microscopic study at 293 K and 77 K of celestine, SrS04, from the middle triassic limestone (Muschelkalk) in Winterswijk, The Netherlands. Netherlands Journal of Geosciences. 80, 1 (Jun. 2001), 41-47. DOI:https://doi.org/10.1017/S0016774600022307.