@article{10_4064_cm_17_2_195_202,
     author = {P. Erd\"os},
     title = {Some remarks on the iterates of the \ensuremath{\varphi} and \ensuremath{\sigma} functions},
     journal = {Colloquium Mathematicum},
     pages = {195--202},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {1967},
     doi = {10.4064/cm-17-2-195-202},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-17-2-195-202/}
}