@article{MZ_1960__74_169870,
     author = {Eckford Cohen},
     title = {Arithmetical functions associated with the unitary divisors of an integer.},
     journal = {Mathematische Zeitschrift},
     pages = {66--80},
     year = {1960},
     volume = {74},
     zbl = {0094.02601},
     url = {http://geodesic.mathdoc.fr/item/MZ_1960__74_169870/}
}