@article{IM2_2003_67_1_a3, author = {V. G. Kanovei and M. Reeken}, title = {Some new results on {Borel} irreducibility of equivalence relations}, journal = {Izvestiya. Mathematics}, pages = {55--76}, year = {2003}, volume = {67}, number = {1}, language = {en}, url = {http://geodesic.mathdoc.fr/item/IM2_2003_67_1_a3/} }