@article{10_4064_aa_22_2_201_206, author = {P. Erd\"os and R. Hall}, title = {On the values of {Euler's} \ensuremath{\varphi}-function}, journal = {Acta Arithmetica}, pages = {201--206}, publisher = {mathdoc}, volume = {22}, number = {2}, year = {1972}, doi = {10.4064/aa-22-2-201-206}, language = {en}, url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-22-2-201-206/} }