TY  - JOUR
AU  - Helmut Maier
AU  - Carl Pomerance
TI  - On the number of distinct values of Euler's φ-function
JO  - Acta Arithmetica
PY  - 1987
SP  - 263
EP  - 275
VL  - 49
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/aa-49-3-263-275/
DO  - 10.4064/aa-49-3-263-275
LA  - en
ID  - 10_4064_aa_49_3_263_275
ER  -