Koffel, William K. Preliminary experimental investigation of transpiration cooling for an afterburner with a sintered, porous stainless-steel combustion-chamber wall, report, June 8, 1953; (https://digital.library.unt.edu/ark:/67531/metadc59787/m1/1/: accessed December 11, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .