@article{MZ_1972__126_171727,
     author = {G\'eza Freud},
     title = {On {Direct} and {Converse} {Theorems} in the {Theory} of {Weighted} {Poynomial} {Approximation.}},
     journal = {Mathematische Zeitschrift},
     pages = {123--134},
     publisher = {mathdoc},
     volume = {126},
     year = {1972},
     zbl = {0222.41004},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__126_171727/}
}