Lowenstam, H A (1967). «Lepidocrocite, an apatite mineral, and magnetic in teeth of chitons (Polyplacophora).». Science156 (3780): 1373-1375. PMID5610118. doi:10.1126/science.156.3780.1373. «X-ray diffraction patterns show that the mature denticles of three extant chiton species are composed of the mineral lepidocrocite and an apatite mineral, probably francolite, in addition to magnetite.»
Lowenstam, H A (1967). «Lepidocrocite, an apatite mineral, and magnetic in teeth of chitons (Polyplacophora).». Science156 (3780): 1373-1375. PMID5610118. doi:10.1126/science.156.3780.1373. «X-ray diffraction patterns show that the mature denticles of three extant chiton species are composed of the mineral lepidocrocite and an apatite mineral, probably francolite, in addition to magnetite.»