K. Linthout; H. Paulick; 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. njg 2009, 88, 55 - 74.