Cobzaş, Ştefan. “Best Approximation in Spaces of Bounded Vector-Valued Sequences”. Rev. Anal. Numér. Théor. Approx. 23, no. 1 (August 1, 1994): 63–69. Accessed August 12, 2022. https://ictp.acad.ro/jnaat/journal/article/view/1994-vol23-no1-art6.