@incollection{AST_1977__49__117_0,
     author = {Katok, A.B},
     title = {The special representation theorem for multidimensional group actions},
     booktitle = {Syst\`eme dynamique I - Varsovie},
     series = {Ast\'erisque},
     pages = {117--140},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {49},
     year = {1977},
     mrnumber = {492181},
     zbl = {0388.28024},
     language = {en},
     url = {http://www.numdam.org/item/AST_1977__49__117_0/}
}