@article{BUMI_1963_3_18_4_a3,
     author = {Bellman, Richard},
     title = {A note on differential approximation and orthogonal polynomials.},
     journal = {Bollettino della Unione matematica italiana},
     pages = {363--366},
     publisher = {mathdoc},
     volume = {Ser. 3, 18},
     number = {4},
     year = {1963},
     zbl = {0125.31102},
     mrnumber = {161076},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BUMI_1963_3_18_4_a3/}
}