Kluge, Friedrich (2012). Etymological Dictionary of the German Language. 25th edition, edited by Elmar Seebold, Berlin/Boston, ISBN 978-3-11-022364-4, p. 602 (Google Books).
Wilhelm Binder: Allgemeine Realencyclopädie oder Conversationslexicon für das katholische Deutschland.
Volume 6. Regensburg 1848, p. 1133 (digitalised).
Etymological Dictionary of the Germans, prepared under the direction of Wolfgang Pfeifer. Berlin 1989, reprinted several times since (cf. "Mark", provided by the Digital Dictionary of the German Language, retrieved 9 January 2020).