[2] Ju. D. Burago, V. G. Maz’ya: Nekotoryje voprosy teorii potenciala i teorii funkcij dlja oblastěj s nereguljarnymi granicami. Zapiski Naučnych Seminarov LOMI 3 (1967). (Russian)
[3] M. Dont: 
Non-tangential limits of the double layer potentials. Časopis pro pěst. mat. 97 (1972), 231–258. 
MR 0444975 | 
Zbl 0237.31012[6] V. P. Havin, N. K. Nikolski: 
Linear and Complex Analysis Problem Book 3. Lecture Notes in Math., vols. 1573, 1574, Springer-Verlag, 1994. 
MR 0734178[9] J. Král: Ob uglovych preděl’nych značenijach integralov tipa Koši. Doklady AN SSSR 155 (1964), no. 1, 32–34. (Russian)
[10] J. Král, J. Lukeš: 
On the modified logarithmic potential. Czechoslov. Math. J. 21 (1971), 76–98. 
MR 0277740[11] J. Král, D. Medková: 
Angular limits of double layer potentials. Czechoslov. Math. J. 45 (1995), 267–292. 
MR 1331464[12] J. Lukeš: 
A note on integral of the Cauchy type. Comment. Math. Univ. Carolinae 9 (1968), 563–570. 
MR 0243011[13] I. D. Mačavariani: O graničnych značenijach logarifmičeskogo potenciala i integrala tipa Koši. Soobšč. Akad. Nauk. Gruz. SSR 69 (1973), 21–24. (Russian)
[14] I. D. Mačavariani: O nepreryvnosti osobogo integrala s jadrom Koši. Trudy Inst. Vyčisl. Matem. AN Gruz. SSR 25 (1985), 87–115. (Russian)
[15] V. G. Maz’ya: Boundary Integral Equations. Analysis IV, Encyklopaedia of Mathematical Science, vol. 27, Springer-Verlag, 1991.
[16] N. J. Muskhelišvili: Singuljarnyje integral’nyje uravněnija. Moscow, 1962. (Russian)
[17] S. Saks: 
Theory of the integral. Dover Publications, New York, 1964. 
MR 0167578[18] H. Watanabe: 
Double layer potentials for a bounded domain with fractal boundary. Abstracts of lectures delivered in International Conference on Potential Theory (August 13–20, 1994, Kouty, Czech Republic), p. 44. 
Zbl 0854.31001