1. 3) Arnstein, K. and Klemperer, W.: Aerodynamic Theory, Vol. 6, Julius Springer, Berlin, 1936, pp. 78–80.
2. 4) Munk, M. M.: The Drag of Zeppelin Airships, NACA Report No. 117, 1921.
3. 5) De France, S. J. and Burgess, C. P.: Speed and Deceleration Trials of U. S. S. Los Angeles, NACA Report No. 318, 1929.