@article{10_4064_cm_13_1_95_99,
     author = {A. M\k{a}kowski and A. Schinzel},
     title = {On the functions \ensuremath{\varphi}(n) and \ensuremath{\sigma}(n)},
     journal = {Colloquium Mathematicum},
     pages = {95--99},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1964},
     doi = {10.4064/cm-13-1-95-99},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-13-1-95-99/}
}