TY  - JOUR
AU  - K.D. jr. Magill
AU  - S. Yamamuro
TI  - Union and symmetry preserving homomorphisms of semigroups of closed relations.
JO  - Semigroup forum
PY  - 1971
SP  - 168
EP  - 172
VL  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1971__3_133859/
ID  - SF_1971__3_133859
ER  -