Pottinger, P. (2001). Absolute projektionskostanten endlichdimensionaler teilräume von \(C^{k}(I)\): Absolute projection costants of finite-dimensional subspaces of \(C^{k}(I)\). Rev. Anal. Numér. Théor. Approx., 30(2), 213-218. https://ictp.acad.ro/jnaat/journal/article/view/2001-vol30-no2-art9