@article{GDZPPN002350769, title = {Borel Structures in Groups and Semigroups.}, journal = {Mathematica Scandinavica}, volume = {28}, year = {1971}, pages = {124-128}, zbl = {0217.08502}, url = {http://dml.mathdoc.fr/item/GDZPPN002350769} }
Christensen, Jens Peter Reus. Borel Structures in Groups and Semigroups.. Mathematica Scandinavica, Tome 28 (1971) pp. 124-128. http://gdmltest.u-ga.fr/item/GDZPPN002350769/