@article{CMUC_1972_13_1_a0,
     author = {Babu\v{s}ka, Ivo},
     title = {Approximation by {Hill} functions. {II}},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {1--22},
     year = {1972},
     volume = {13},
     number = {1},
     mrnumber = {0305550},
     zbl = {0244.41005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1972_13_1_a0/}
}