@article{PORMA_1987__44_1_115570,
     author = {McDaniel, Wayne L.},
     title = {Representations of every integer as the difference of nonsquare powerful numbers},
     journal = {Portugaliae mathematica},
     pages = {69--75},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1987},
     mrnumber = {0911834},
     zbl = {0629.10010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1987__44_1_115570/}
}