Heller, Jack A.; Whitney, Rose L. & Cavicchi, Richard H. Experimental investigation of a conservatively designed turbine at four rotor-blade solidities, report, July 17, 1952; (https://digital.library.unt.edu/ark:/67531/metadc59238/m1/1/: accessed October 21, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .