TY  - JOUR
AU  - Hemminger, Robert L.
TI  - On the Group of a Directed Graph
JO  - Canadian journal of mathematics
PY  - 1966
SP  - 211
EP  - 220
VL  - 18
IS  - 1
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1966-023-2/
DO  - 10.4153/CJM-1966-023-2
ID  - 10_4153_CJM_1966_023_2
ER  -