[1] G. Fichera: 
Una introduzione alla teoria delle equazioni integrali singolari. Rend. Mat. e Appl. 77 (1958), 82-191. 
MR 0106328 | 
Zbl 0097.08602[2] J. Král: 
Some inequalities concerning the cyclic and radial variations of a plane path-curve. Czech. Math. Journal 14 (89), 1964, 271--280. 
MR 0180689[3] J. Král: 
Non-tangential limits of the logarithmic potential. ibid. 455 - 482. 
MR 0180691[4] J. Král: 
Angular limit values of integrals of the Cauchy type. (Russian), Doklady Akad. nauk SSSR 155 (1964), 32-34. 
MR 0159931[5] J. Král: Potential theory I. (Czech; mimeographed lecture notes), Státní  pedagogické nakladatelství Praha, 1965.
[6] J. Lukeš: 
Lebesgueův integrál. Čas. pro pěst. mat. 91 (1966), 371 - 383. 
MR 0209416[7] J. Lukeš: 
A note on integrals of the Cauchy type. Comment. Math. Univ. Carolinae 9 (1968), 563-570. 
MR 0243011[8] J. Mařík: 
Transformation of one-dimensional integrals. (Russian), Čas. pro pěst. mat. 82 (1957), 93-98. 
MR 0088534[9] N. J. Muskhelišvili: Singular integral equations. (Russian), Moscow 1962.
[10] T. Radó, P. V. Reichelderfer: 
Continuous transformations in analysis. Springer-Verlag 1955. 
MR 0079620[11] S. Saks: 
Theory of the integral. New York 1964. 
MR 0167578