BBC: Edward IV (1442 - 1483) - Biography for the eldest surviving son of Richard Plantaganet, Duke of York, who was declared successor to Henry VI in 1460. - http://www.bbc.co.uk/history/historic_figures/edward_iv_king.shtml
The Yorkists: Edward IV - Information about the reign of Edward IV. - http://www.royal.gov.uk/output/Page48.asp
Edward IV - Short biography for the king of England (1461–70, 1471–83), son of Richard, duke of York. - http://www.factmonster.com/ce6/people/A0816794.html