Mayo, Wilbur L. Hydrodynamic impact of a system with a single elastic mode I : theory and generalized solution with an application to an elastic airframe, report, March 17, 1947; (https://digital.library.unt.edu/ark:/67531/metadc60433/m1/1/: accessed September 25, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .