⁴Burl, Aubrey. A Guide to the Stone Circles of Britain, Ireland, and Brittany. New Haven: Yale UP, 1995. 218-19.
A review in The New York Times referred to Burl as "...the leading authority on British Stone circles.” (Johnspon, Paul. "MagicStones: Prehistoric Avebury." The New York Times 21 Sept. 1979, Book Review sec.: 3.)