Inequalities of Grunsky-Nehari type for pairs of vector functions Kazimierz Włodarczyk (1980) Annales Polonici Mathematici
Integralgleichungen erster Art und konformer Abbildung. Dieter Gaier (1976) Mathematische Zeitschrift
Isoperimetric inequality for torsional rigidity in the complex plane. Salakhudinov, R.G. (2001) Journal of Inequalities and Applications [electronic only]