@article{MR_1996_46_a5,
     author = {Florian Luca},
     title = {On the {Sum-of-Divisors} {Function} of the {Numbers} of {Fermat} and {Ferentinou-Nicolacopoulou}},
     journal = {M\ensuremath{\alpha}\ensuremath{\theta}\ensuremath{\eta}\ensuremath{\mu}\ensuremath{\alpha}\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta} E\ensuremath{\pi}\ensuremath{\iota}\ensuremath{\theta}\ensuremath{\varepsilon}\ensuremath{\acute\omega}\ensuremath{\rho}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta}},
     pages = {11--21},
     year = {1996},
     volume = {46},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_1996_46_a5/}
}