TY  - JOUR
AU  - E.M. Norris
TI  - Union preserving homomorphisms of semigroups of closed relations.
JO  - Semigroup forum
PY  - 1977
SP  - 169
EP  - 180
VL  - 15
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1977__15_134247/
ID  - SF_1977__15_134247
ER  -