1. Kaczmarz, S., Steinhaus, H. Theorie der Orthogonalreihen, MonografiMatematice, Vol. 6 (Warsaw, 1935; Fizmatgiz, Moscow, 1958).
2. Golubov, B. I. “A Class of Complete Orthogonal Systems”, Sib. Mat. Zh. 9, No. 2, 297–314 (1968) [in Russian].
3. Golubov, B., Efimov, A., Skvortsov, V. Walsh Series and Transforms. Theory and Applications (Nauka, Moscow, 1987; Kluver Academic Publishers, Dordrecht, Boston, London, 1991).
4. Golubov, B. I., Rubinshtein, A. I. “A Class of Convergence Systems”, Mat. Sb. (N. S.), 71, No. 1, 96–115 (1966) [in Russian].
5. Terekhin, A. P. “The Approximation of Functions of Bounded p-Variation”, Izv. Vyssh. Uchebn.Zaved.Mat., No. 2, 171–187 (1965) [in Russian].