1. R. A Lasuriya, “Approximation characteristics of the spaces $$S^{(p,q)}(\sigma^m)$$ of functions defined on a sphere,” in Extremal Problems in the Theory of Functions and Related Problems, (Pr. Inst. Mat. Nats. Akad. Nauk Ukr. Mat. Zastos. Natsional. Akad. Nauk Ukraini, Kyiv, 2003), Vol. 46, pp. 89–115 [in Russian].
2. R. A Lasuriya, “Direct and inverse theorems on the approximation of functions defined on a sphere in the space $$S^{(p,q)}(\sigma^m)$$,” Ukrainian Math. J. 59 59 (7), 996–1009 (2007).
3. R. A. Lasuriya, “Direct and inverse theorems on the approximation of functions by Fourier–Laplace sums in the spaces $$S^{(p,q)}(\sigma^{m-1})$$,” Math. Notes 98 (4), 601–612 (2015).
4. R. A. Lasuriya, “Jackson-type inequalities in the spaces $$S^{(p,q)}(\sigma^{m-1})$$,” Math. Notes 105 (5), 707–719 (2019).
5. R. A. Lasuriya, “Inverse approximation theorems in the spaces $$S^{(p,q)}(\sigma^{m-1})$$,” Math. Notes 110 (1), 80–91 (2021).