Revision History for USGS 
  Crustal Studies Technical Letter Number 19

  John C. Roller

  Crustal Structure in the Eastern Colorado Plateaus 
  Provence from Seismic-Refraction Measurements

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  Posted online at http://pubs.usgs.gov/misc/tl/0019/
  November 9, 2012

  Initial release in paper form
  June 15, 1964

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