“On Approximation of Signals in the Generalized Zygmund Class Using (E,r)(N,qn) Mean of Conjugate Derived Fourier Series”, Eur. J. Pure Appl. Math., vol. 13, no. 5, pp. 1325–1336, Dec. 2020, doi: 10.29020/nybg.ejpam.v13i5.3714.