@article{CMUC_1963_4_4_a6,
     author = {Baayen, Cor P. and Hedrl{\'\i}n, Zden\v{e}k},
     title = {Commutative polynomial semigroups on a segment},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {173--179},
     year = {1963},
     volume = {4},
     number = {4},
     mrnumber = {0166769},
     zbl = {0151.01904},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1963_4_4_a6/}
}