Pych, Paulina. “The Denjoy Integral in Some Approximation Problems”. Anal. Numér. Théor. Approx. 5, no. 1 (February 1, 1976): 79–86. Accessed April 30, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1976-vol5-no1-art8.