@article{MOMA_1989__107_3_178413,
     author = {Hartmut Menzer},
     title = {The {Distribution} of {Powerful} {Integers} of {Type} 4.},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {69--76},
     publisher = {mathdoc},
     volume = {107},
     number = {3},
     year = {1989},
     zbl = {0679.10035},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1989__107_3_178413/}
}