Kuhn, Richard E. & Draper, John W. Investigation of the aerodynamic characteristics of a model wing-propeller combination and of the wing and propeller separately at angles of attack up to 90 degrees, report, 1956; (https://digital.library.unt.edu/ark:/67531/metadc60654/m1/1/: accessed November 14, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .