1. Reissner, E., Bulletin of the Am. math. Soc.55 (1949) 825.
2. Theodorsen, Th., N.A.C.A. Rep. 496 (1935).
3. Heemert, A. van, and J. H. Greidanus, Nat. aeron. Res. Inst. Rep. F. 41 (1948).
4. Betz, A., Konforme Abbildung 1949.
5. Whittaker, E. T., and G. N. Watson, A course of modern Analysis, 4th ed. 1927.