Stähle, Volker, Rainer Altherr, Günther Unrath, & Alexander Varychev. " Petrological studies of Middle Neolithic stone artefacts from the Salenhof archaeological site near Trillfingen (SW Germany) give evidence for an early diversified long-distance exchange system." Journal of Neolithic Archaeology [Online], 20 (2018): 131-158. Web. 16 Dec. 2019