E. S. Bhaya and R. R. Mohsin, “APPROXIMATION OF 3-MONOTONE FUNCTIONS BY 3-MONOTONE FUNCTIONS IN Lp SPACES”, Jour. Kufa Math. Comp., vol. 1, no. 1, pp. 54–64, Apr. 2010, doi: 10.31642/JoKMC/2018/010109.