D J Donahue; J S Olin; G Harbottle (2002), "Determination of the Radiocarbon Age of Parchment of the Vinland Map", Radiocarbon, 44 (1): 45-52, doi:10.1017/S0033822200064651, Wikidata Q108769140
D J Donahue; J S Olin; G Harbottle (2002), "Determination of the Radiocarbon Age of Parchment of the Vinland Map", Radiocarbon, 44 (1): 45-52, doi:10.1017/S0033822200064651, Wikidata Q108769140