ROBERT FREDERICK. (2005). SEVEN WONDERS OF THE WORLD. REALLY USEFUL MAP COMPANY LTD.
芝加哥风格引文ROBERT FREDERICK. SEVEN WONDERS OF THE WORLD. ENGLAND: REALLY USEFUL MAP COMPANY LTD, 2005.
MLA引文ROBERT FREDERICK. SEVEN WONDERS OF THE WORLD. REALLY USEFUL MAP COMPANY LTD, 2005.
警告：这些引文格式不一定是100％准确.