http://ru.wikipedia.org/wiki/%D0%9B%D0%B5%D1%80%D0%BC%D0%BE%D0%BD%D1%82%D0%BE%D0%B2,_%D0%9C%D0%B8%D1%85%D0%B0%D0%B8%D0%BB_%D0%AE%D1%80%D1%8C%D0%B5%D0%B2%D0%B8%D1%87
http://ru.wikipedia.org/wiki/%D0%9B%D0%B5%D1%80%D0%BC%D0%BE%D0%BD%D1%82%D0%BE%D0%B2_(%D0%B3%D0%BE%D1%80%D0%BE%D0%B4)
http://ru.wikipedia.org/wiki/%D0%9B%D0%B5%D1%80%D0%BC%D0%BE%D0%BD%D1%82%D0%BE%D0%B2,_%D0%9C%D0%B8%D1%85%D0%B0%D0%B8%D0%BB_%D0%9D%D0%B8%D0%BA%D0%BE%D0%BB%D0%B0%D0%B5%D0%B2%D0%B8%D1%87