The Effects of Piston-Head Shape, Cylinder-Head Shape, and Exhaust Restriction, on the Performance of a Piston-Ported Two-Stroke Cylinder, report, March 1940; (https://digital.library.unt.edu/ark:/67531/metadc54614/m1/8/: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .