Motornaya, O. V., and V. P. Motornyi. 2014. “Generalized Lebesgue Constants and the Convergence of Fourier–Jacobi Series in the Spaces $L_{1,A,B}$”.
Ukrains’kyi Matematychnyi Zhurnal 66 (2): 259–268.
https://umj.imath.kiev.ua/index.php/umj/article/view/2128.