Parks, James H. Experimental evidence of sustained coupled longitudinal and lateral oscillations from a rocket-propelled model of a 35 degree swept wing airplane configuration, report, May 28, 1954; (https://digital.library.unt.edu/ark:/67531/metadc60471/m1/1/: accessed September 20, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .