Atthill, Robin (1971): , 2. utg., Newton Abbot: David & Charles. ISBN 978-0715372975. Baker, Ernest Albert; Balch, Herbert E. (1907): . Clifton: J. Baker & son. Hardcastle, Jim; Nisbet, Merryn (2008): . Mendip Hills AONB Service. ISBN 978-0-9559110-0-2.