his new LondonUnderground map(页面存档备份,存于互联网档案馆) "The Story of Beck's LondonUnderground Map" London's Transport Museum(页面存档备份,存于互联网档案馆) Tube maps with walking
1016/S0019-1035(03)00148-9. Lovett, Richard A. Saturn Moon Titan May Have Underground Ocean. National Geographic. 2008-03-20. (原始内容存档于2012-10-18). McKay, C. P.; Smith,