Lal, S. and Singh, G. K. (2003) “Degree of approximation of conjugate of Lip $ \alpha$ class function by $ {K^\lambda}$-summability means of conjugate series of a Fourier series”, Tamkang Journal of Mathematics, 34(4), pp. 387–394. doi: 10.5556/j.tkjm.34.2003.241.