TY  - JOUR
AU  - Jens Peter Reus Christensen
TI  - Borel Structures in Groups and Semigroups.
JO  - Mathematica Scandinavica
PY  - 1971
SP  - 124
EP  - 128
VL  - 28
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MS2_1971__28_166169/
ID  - MS2_1971__28_166169
ER  -