@article{PORMA_1957__16_1_114783,
     author = {McCarthy, Paul J.},
     title = {Note on perfect and multiply perfect numbers},
     journal = {Portugaliae mathematica},
     pages = {19--21},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1957},
     mrnumber = {0101209},
     zbl = {0082.25606},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1957__16_1_114783/}
}