@article{RSMUP_1986__75__253_0,
     author = {Ambrosiewicz, Jan},
     title = {On the squares of sets of linear groups},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {253--256},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {75},
     year = {1986},
     mrnumber = {847670},
     zbl = {0591.20048},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1986__75__253_0/}
}