Attribution  This article incorporates public domain material from the National Aeronautics and Space Administration document "SP-4306 Engines and Innovation: Lewis Laboratory and American Propulsion Technology: Chapter 3: Jet Propulsion: Too Little, Too Late" by Virginia P. Dawson.
Diakses tanggal 25 May 2010.  Atribusi  Artikel ini berisi bahan berstatus domain umum dari National Aeronautics and Space Administration dokumen "SP-4306 Engines and Innovation: Lewis Laboratory and American Propulsion Technology: Chapter 3: Jet Propulsion: Too Little, Too Late" oleh Virginia P. Dawson.