(en) James I. McNelis III, « "The tree took me up from ground and carried me off" : A Source for Tolkien’s Ents in Ludvig Holberg's Journey of Niels Klim to the World Underground », Tolkien Studies : An Annual Scholarly Review, West Virginia University Press, vol. 3,‎ 2006, p. 153-156 (DOI 10.1353/tks.2006.0022).