1. V. F. Babenko, “Nonsymmetric approximations in spaces of integrable functions,” Ukr. Mat. Zh., 34, No. 4, 409–416 (1982); English translation: Ukr. Math. J., 34, No. 4, 331–336 (1982).
2. V. F. Babenko, “Inequalities for rearrangements of differentiable periodic functions, problems of approximation, and approximate integration,” Dokl. Akad. Nauk SSSR, 272, No. 5, 1038–1041 (1983).
3. V. F. Babenko, “Approximation of the classes of convolutions,” Sib. Mat. Zh., 28, No. 5, 6–21 (1987).
4. V. F. Babenko, Extremal Problems of the Approximation Theory and Nonsymmetric Norms [in Russian], Doctoral-Degree Thesis (Physics and Mathematics), Dnepropetrovsk (1987).
5. V. F. Babenko and N. V. Parfinovich, “Exact values of the best approximations of the classes of periodic functions by splines with defect 2,” Mat. Zametki, 85, No. 4, 538–551 (2009).