Revision History for USGS 
  Crustal Studies Technical Letter Number 0009

  J.C. Roller, W.H. Jackson, J.F. Cooper, and B.A. Martina

  Crustal Structure in the Western United States; Study of 
  Seismic Propagation Paths and Regional Traveltimes in the 
  California-Nevada Region

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  Posted online at http://pubs.usgs.gov/misc/tl/0009/
  July 30, 2012

  Initial release in paper form
  February 8, 1963

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