TY  - JOUR
AU  - G.B. Preston
TI  - Schützenberger groups of ...-classes in the semigroup of all binary relations on a set.
JO  - Semigroup forum
PY  - 1974
SP  - 260
EP  - 262
VL  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1974__6_133982/
ID  - SF_1974__6_133982
ER  -