K. Linthout, H. Paulick, and J.R. Wijbrans. “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, vol. 88, Mar. 2009, pp. 55 -74, doi:10.1017/S0016774600000998.