@article{MAN_1968__176_161691,
     author = {P. HARTMAN},
     title = {On {Limits} of {Riemann} {Sums} and the {Range} of {Integrals.}},
     journal = {Mathematische Annalen},
     pages = {208--220},
     publisher = {mathdoc},
     volume = {176},
     year = {1968},
     zbl = {0174.45202},
     url = {http://geodesic.mathdoc.fr/item/MAN_1968__176_161691/}
}