Bibliography
- Llyfrgell Bodleian, All at Sea. The Story of Navigational Charts, (Rhydychen, 1995)
- Olwen Caradoc Evans, Sea charts and the Principality of Wales, Map Collectors' Circle, No. 54 (Llundain, 1965)
- A H W Robinson, Marine cartography in Britain, (Caerlŷr, 1962)
- Coolie Verner, Captain Collins' Coasting Pilot, Map Collectors' Circle, No. 58 (Llundain, 1969)