K. Linthout, H. Paulick, & J.R. Wijbrans. (2009). Provenance of basalt blocks from Roman sites in Vleuten-De Meern (the Netherlands) traced to the Tertiary Siebengebirge (Germany): a geoarchaeological quest using petrological and geochemical methods. Netherlands Journal of Geosciences, 88, 55 - 74. https://doi.org/10.1017/S0016774600000998