John B. Penforl books & textbook
Antiquarian Horology : The Bumbrian Background of George Graham; a Visit to West Tofts; a Danish Maker of Clocks and Watches; Time in Jewish Tradition; Thiout's Detached Watch Escapement; a Note on Two Brocot Inventions (Vol. 8, No. 6 March 1974)
John B. Penforl D. F. Nettell Johan Knap
Atiquarian Horological Society /1974T Journal
