Figures have been taken from two sources: Demographia's "World Urban Areas" study, and from citypopulation.de, created by Thomas Brinkhoff of the Institut für Angewandte Photogrammetrie und Geoinformatik.
数据来自两个来源：Demographia的“World Urban Areas”研究，以及citypopulation.de，由应用摄影测量与地理信息学研究所（Institut für Angewandte Photogrammetrie und Geoinformatik）的Thomas Brinkhoff创建。