1. Henn, €1."Descent Characterisitcs of Parachutes, I' R. A. E. translation No. 233 of German Report ZWB/UM/G202. October 1944.
2. Ludwig, R., and Heins, W. "Theoretical Studies of the Dynamic Stability of Parachutes, '' translated from the German by Faraday Translations, November 1964.