Brooks, Nicholas. Anglo-Saxon myths: state and church, 400–1066. 2000. Hill, D. Atlas of Anglo-Saxon England. Oxford. 1981. map 136. Hooke, Della. Anglo-Saxon Territorial Organisation: The Western Margins of Mercia. Occasional Paper 22. University of Birmingham, Dept. of Geography. 1986: 1–45.
Shippey, Prof. Tom. The Road to Middle Earth. HarperCollins. 2005: 139–140. ISBN 0-261-10275-3. Shippey notes that Tolkien uses 'Mercian' forms of Anglo-Saxon, e.g., "Saruman, Hasufel, Herugrim for 'standard' [Anglo-Saxon] Searuman, Heasufel and Heorugrim" Footnote page 140
