@incollection{AST_1995__232__155_0,
     author = {de la Harpe, P. and Voiculescu, D.},
     title = {A problem on the $II_1$-factors of {Fuchsian} groups},
     booktitle = {Recent advances in operator algebras - Orl\'eans, 1992},
     series = {Ast\'erisque},
     pages = {155--158},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {232},
     year = {1995},
     mrnumber = {1372531},
     zbl = {0849.46042},
     language = {en},
     url = {http://www.numdam.org/item/AST_1995__232__155_0/}
}