@inbook{NBERc12372,
 Crossref = "NBERlern11-1",
 title = "The Adversity/Hysteresis Effect: Depression-Era Productivity Growth in the U.S. Railroad Sector",
 author = "Alexander J. Field",
 BookTitle = "The Rate and Direction of Inventive Activity Revisited",
 Publisher = "University of Chicago Press",
 pages = "579-606",
 year = "2011",
 month = "April",
 URL = "http://www.nber.org/chapters/c12372",
}
@book{NBERlern11-1,
 title = "The Rate and Direction of Inventive Activity Revisited",
 author = "Josh Lerner and Scott Stern",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2012",
 URL = "http://www.nber.org/books/lern11-1",
}