http://en.wikipedia.org/wiki/Winter_solstice December 21
http://news.nationalgeographic.com/news/2012/1221-winter-solstice-first-day-winter-facts,
http://earthsky.org/astronomy-essentials/everything-you-need-to-know-about-the-solstice-on-december-2012,
http://www.guardian.co.uk/culture/video/2012/dec/21/end-of-the-13th-baktun-video,
http://www.guardian.co.uk/world/video/2012/dec/21/mayan-calendar-end-guatemala-video
http://en.wikipedia.org/wiki/Paul_Revere December 21, 1734 – May 10, 1818
https://www.princeton.edu/~achaney/tmve/wiki100k/docs/Paul_Revere.html,
http://www.paul-revere-heritage.com/when-was-paul-revere-born.html