J. M. de Navarro (1925). "Prehistoric Routes between Northern Europe and Italy Defined by the Amber Trade". The Geographical Journal. 66 (6). Jstor: 481–503. doi:10.2307/1783003. JSTOR1783003.
J. M. de Navarro (1925). "Prehistoric Routes between Northern Europe and Italy Defined by the Amber Trade". The Geographical Journal. 66 (6). Jstor: 481–503. doi:10.2307/1783003. JSTOR1783003.