Baug, I. (2011). «Soapstone finds». i Skre, D. (red.) Things from the Town: artefacts and inhabitants in Viking-age Kaupang, 311–37. Aarhus University Press, Oslo. Hansen, Gitte, et.al. (2017). Soapstone in the North. Quarries, Products and People 7000 BC - AD 1700. UBAS, University of Bergen Archaeological Series Hougen, Bjørn. «Romerike i forhistorisk tid» i Petersen, Jan (1922). «Et besøk ved klæberstensbruddet paa Folvelsæter».