Raşa, I. “On Some Results of C.A. Micchelli”. Anal. Numér. Théor. Approx. 9, no. 1 (February 1, 1980): 125–127. Accessed April 26, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1980-vol9-no1-art16.