1. Clocks and watches: the leap to precision;Andrewes,1994
2. Time and Timekeepers;Milham,1945
3. Unrolling Time: Christiaan Huygens and the Mathematization of Nature;Yoder,1990
4. The Illustrated Longitude;Sobel,1998
5. C. Huygens, Letter to de Sluse, In: Oeuveres Completes de Christian Huygens (letters; no. 1333 of 24 February 1665, no. 1335 of 26 February 1665, no. 1345 of 6 March 1665), (Societe Hollandaise Des Sciences, Martinus Nijhoff, La Haye, 1893).