@article{MZ_1965__90_170482,
     author = {Daniel J. Kleitman},
     title = {On a lemma of {Littlewood} and {Offord} on the distribution of certain sums.},
     journal = {Mathematische Zeitschrift},
     pages = {251--259},
     year = {1965},
     volume = {90},
     zbl = {0148.01104},
     url = {http://geodesic.mathdoc.fr/item/MZ_1965__90_170482/}
}