TY  - JOUR
AU  - Mucuk, Osman
TI  - Coverings and ring-groupoids.
JO  - Georgian Mathematical Journal
PY  - 1998
SP  - 475
EP  - 482
VL  - 5
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/GMJ_1998__5_5_48189/
LA  - en
ID  - GMJ_1998__5_5_48189
ER  -