@article{PMIHES_1987__66__93_0,
     author = {Gromov, Michael and Piatetski-Shapiro, I.},
     title = {Non-arithmetic groups in {Lobachevsky} spaces},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {93--103},
     publisher = {Institut des Hautes \'Etudes Scientifiques},
     volume = {66},
     year = {1987},
     mrnumber = {932135},
     zbl = {0649.22007},
     language = {en},
     url = {http://www.numdam.org/item/PMIHES_1987__66__93_0/}
}