(原始内容存档于2020-09-12). Hegarty, Paul; Halliwell, Martin, Beyond and Before: Progressive Rock Since the 1960s, New York: The Continuum International Publishing
Considerations in the Design of Long Span Bridges against Progressive Collapse (pdf). HNTB Corporation: 1, 6, 14. [2010-12-25]. (原始内容存档 (PDF)于2011-04-09).
[2010年4月18日]. [失效連結] Alaska Railroad begins to build Tanana River Bridge. Progressive Railroading. 27 September 2011 [30 September 2011]. (原始内容存档于9 May 2012)