Fries, Lorenz, ca. 1490-1531,  Ptolemy,  Waldseemüller, Martin,  Grüninger, Johann, d. 1532?,  Pirckheimer, Willibald,  and Regiomontanus, Joannes.  "Tabula moder. Gronlandiae et Russiae."  Map.  1525.  Norman B. Leventhal Map & Education Center,  https://collections.leventhalmap.org/search/commonwealth:9g54xk065 (accessed August 05, 2020).