Zalovcik, John A. A radar method of calibrating airspeed installations on airplanes in maneuvers at high altitudes and at transonic and supersonic speeds, report, August 31, 1949; (https://digital.library.unt.edu/ark:/67531/metadc60324/m1/1/: accessed October 15, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .