@article{AFST_1993_6_2_3_323_0,
     author = {Duverney, Daniel},
     title = {$U${-D\'erivation}},
     journal = {Annales de la Facult\'e des sciences de Toulouse : Math\'ematiques},
     pages = {323--335},
     publisher = {Universit\'e Paul Sabatier},
     address = {Toulouse},
     volume = {6e s{\'e}rie, 2},
     number = {3},
     year = {1993},
     mrnumber = {1260762},
     zbl = {0803.12003},
     language = {fr},
     url = {http://archive.numdam.org/item/AFST_1993_6_2_3_323_0/}
}