Вот еще: http://russ.hashcode.ru/questions/16983/%D0%BE%D1%80%D1%84%D0%BE%D0%B3%D1%80%D0%B0%D1%84%D0%B8%D1%8F-%D0%BF%D0%B0%D0%B4%D0%B5%D0%B6%D0%BD%D0%BE%D0%B5-%D0%BE%D0%BA%D0%BE%D0%BD%D1%87%D0%B0%D0%BD%D0%B8%D0%B5-%D0%BA%D0%BE%D0%BD%D1%8C%D1%8F%D0%BA%D0%B0-%D0%B8%D0%BB%D0%B8-%D0%BA%D0%BE%D0%BD%D1%8C%D1%8F%D0%BA%D1%83