T. Berners-Lee; L. Masinter; M. McCahill. <a href="http://www.ietf.org/rfc/rfc1738.txt"><cite>Uniform Resource Locators (URL).</cite></a> December 1994. Internet RFC 1738. URL: <a href="http://www.ietf.org/rfc/rfc1738.txt">http://www.ietf.org/rfc/rfc1738.txt</a>