Cobzaş, Ştefan. “Antiproximinal Sets in the Banach Space \(C( \omega^k;X)\)”. Rev. Anal. Numér. Théor. Approx. 27, no. 1 (February 1, 1998): 47–58. Accessed August 12, 2022. https://ictp.acad.ro/jnaat/journal/article/view/1998-vol27-no1-art6.