Hansen, Arthur G. On Possible Similarity Solutions for Three-Dimensional Incompressible Laminar Boundary-Layer Flows Over Developable Surfaces and with Proportional Mainstream Velocity Components, report, September 1958; (https://digital.library.unt.edu/ark:/67531/metadc63919/m1/1/: accessed January 18, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .