Sheila Noth, Peter Bruckschen, and Detlev K. Richter, “Conodont color alteration and microdolomite composition - implications to the Muschelkalk limestones (Upper Triassic) overlying the Upper Cretaceous intrusive body of the Vlotho Massif (Weserbergland, Northwest Germany)”, njg, pp. 265-273, Jan. 1991.