"World's Tallest Towers: Timeline of all Skyscrapers Holding the Title of Tallest Building in the World From 1890 to the Present". skyscraper.org.
Truy cập ngày 16 tháng 6 năm 2008.  ^ a ă â “World's Tallest Towers: Timeline of all Skyscrapers Holding the Title of Tallest Building in the World From 1890 to the Present”. skyscraper.org.