@article{10_1090_S0894_0347_97_00221_X,
     author = {Kechris, Alexander and Louveau, Alain},
     title = {The classification of hypersmooth {Borel} equivalence relations},
     journal = {Journal of the American Mathematical Society},
     pages = {215--242},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {1997},
     doi = {10.1090/S0894-0347-97-00221-X},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-97-00221-X/}
}