Karsli, Harun, and H. Erhan Altin. “On Fatou Type Convergence of Higher Derivatives of Certain Nonlinear Singular Integral Operators”. Rev. Anal. Numér. Théor. Approx. 42, no. 1 (February 1, 2013): 37–48. Accessed March 29, 2024. https://ictp.acad.ro/jnaat/journal/article/view/2013-vol42-no1-art3.