Hillary Clinton's speech at the Clinton-Sanders Democratic presidential debate in Durham, New Hampshire, hosted by MSNBC, www.nytimes.com. February 4, 2016.
William Whewell (1847). “History of the Inductive Sciences: I. The Greek school philosophy, with reference to physical science. II. The physical sciences in ancient Greece. III. Greek astronomy. IV. Physical science in the middle ages. V. Formal astronomy after the stationary period”, p.96