1. N. K. Bari, Trigonometric Series [in Russian], Fizmatgiz, Moscow (1961).
2. I. I. Privalov, The Boundary Properties of Analytic Functions [in Russian], Gostekhizdat, Moscow-Leningrad (1950).
3. P. L. Ul'yanov, ?Application of A-integration to a class of trigonometric series,? Mat. Sb.,35, 469?490 (1954).
4. P. L. Ul'yanov, ?On the Cauchy A-integral. I,? Usp. Mat. Nauk,11, No. 5, 223?229 (1956).
5. P. L. Ul'yanov, ?The A-integral and conjugate functions,? Uch. Zap. Mosk. Gos. Univ., Mat., No. 181, 8, 139?157 (1956).