References for: Decimal time and angles
- K Alder, The measure of all things (Little Brown, London, 2002).
- P Galison, Einstein's clocks, Poincaré's maps (W W Norton & Co, New York, 2004).
JOC/EFR October 2005
MacTutor History of Mathematics
[http://www-history.mcs.st-andrews.ac.uk/HistTopics/References/Decimal_time.html]