Caves and rocks: state of the artGerhard Milstreu & Henning Pr\\ohl (ed.). Prehistoric pictures as archaeological source/Forhistoriska bilder som arkeologisk kalla (GOTARC Series C: 50). 220 pages, illustrated. 2004. Tanumshede: Tanums Hallristningsmuseum/Gothenburg University Department of Archaeology; 91-85952-89-3.