Ref:
Hochleitner, R. (1986). Sturmanit und Ettringit aus den Kalahari-Manganfeldern. LAPIS 11 (10), 19-24.
Bonazzi, P., Bindi, L., Medenbach, O., Pagano, R., Lampronti, Menchetti, S. (2007): Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa), Mineralogical Magazine, 71, 193-291.