Simon Newcomb, "Tables of the motion of the Earth on its axis and around the Sun" in Astronomical papers prepared for the use of the American ephemeris and Nautical Almanac, Volume VI: Tables of the four inner planets, (United States Naval Observatory, 1898), pp. 27 (PT36), 34–35 (PT43–PT44).
nasa.gov
eclipse.gsfc.nasa.gov
Espenak, Fred. «Year Dating Conventions». NASA Eclipse Web Site. NASA. Consultado el 19 de febrero de 2009.
