1. Alexander, H., Wermer, J.: Linking numbers and boundaries of varieties. Ann. Math. 151 125–150 (2000)
2. Behnke, H., Sommer, F.: Theorie der analitischen Funktionen einer komplexen Veränderlichen. Springer, Berlin-Gottingen-Hiedelberg 1955
3. Bell, S.: The Cauchy transform, Potential Theory, and Conformal Mapping. CRC Press, Boca Raton, 1992
4. Černe, M., Flores, M.: Generalized Ahlfors functions. To appear in Trans. Amer. Math. Soc.
5. Globevnik, J.: Holomorphic extendibility and the argument principle. Complex Analysis and Dynamical Systems II. Contemp. Math. 382, 171–175 (2005)