John (Fritz) Sumner was the pre-eminent exploratory climber in his chosen domain of Mid Wales, climbing cutting-edge routes on the remote crags and cliff-faces south of southern Snowdonia starting in the mid-1950s.
Books
• John A Sumner (1973). Central Wales. West Col. p.153. SBN 901516 69 4. • John A Sumner (1975). Dolgellau Area. West Col. p.139. SBN 901516 99 6. • J. A. Sumner (1980). Aran Cader Idris Climbers' Guide Supplement. West Col. p. 64. SBN 906227 09 7 • • Martin Crocker, John Sumner, et al. (2002). Meirionnydd. Climbers Club. p. 512 ==References==