293
Brian Greene, Elegant Universe (New York: Vintage Books, 2000), pp. 268, 273.
294
Paul Aspinwall (Duke University), interview with author, June 6, 2008.
295
Morrison, interview with author, May 27, 2008.
296
Andrew Strominger (Harvard University), February 7, 2007.
297
Chris Beasley, Jonathan Heckman, and Cumrun Vafa, “GUTs and Exceptional Branes in F-Theory — I,” November 18, 2008, ; Chris Beasley, Jonathan Heckman, and Cumrun Vafa, “GUTs and Exceptional Branes in F-Theory — II: Experimental Predictions,” June 12, 2008, ; Ron Donagi and Martijn Wijnholt, “Model Building with F-Theory,” March 3, 2008, ; and Ron Donagi and Martijn Wijnholt, “Breaking GUT Groups in F-Theory,” August 17, 2008, .
