Trigonometric approximation by Nörlund type means in $L^p$-norm

summary:We show that the same degree of approximation as in the theorems proved by L. Leindler [Trigonometric approximation in $L^p$-norm, J. Math. Anal. Appl. 302 (2005), 129--136] and P. Chandra [Trigonometric approximation of functions in $L^p$-norm, J. Math. Anal. Appl. 275 (2002), 13--26] is valid for a more general class of lower triangular matrices. We also prove that these theorems are true under weakened assumptions