@article{10_4064_cm_86_1_31_36,
     author = {A. Grytczuk and F. Luca and M. W\'ojtowicz},
     title = {On a conjecture of {M\k{a}kowski} and {Schinzel} concerning the composition of the arithmetic functions \ensuremath{\sigma} and \ensuremath{\phi}},
     journal = {Colloquium Mathematicum},
     pages = {31--36},
     publisher = {mathdoc},
     volume = {86},
     number = {1},
     year = {2000},
     doi = {10.4064/cm-86-1-31-36},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-86-1-31-36/}
}