@article{PMIHES_1987__66__93_0,
     author = {Michael Gromov and I. Piatetski-Shapiro},
     title = {Non-arithmetic groups in {Lobachevsky} spaces},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {93--103},
     year = {1987},
     publisher = {Institut des Hautes \'Etudes Scientifiques},
     volume = {66},
     doi = {10.1007/BF02698928},
     mrnumber = {932135},
     zbl = {0649.22007},
     language = {en},
     url = {https://pmihes.centre-mersenne.org/articles/10.1007/BF02698928/}
}