The Illustrated Longitude, by Dava Sobel and William J.H. Andrews.
The Science of Clocks and Watches, by A.L. Rawlings.
The Quest for Longitude.
The Lost Science of John ‘Longitude’ Harrison, by William  Laycock.
The Technology of John Harrison’s Portable Timekeepers, by A.G. Randall.
Antiquarian Horology, Number 4, Volume 29, June 2006.
Antiquarian Horology, Number 4, Volume 31, June 2009.
Horological Science Newsletter