@article{CTGDC_1989__30_1_3_0,
     author = {Johnstone, Peter T.},
     title = {A constructive {{\textquotedblleft}Closed} subgroup theorem{\textquotedblright} for localic groups and groupoids},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {3--23},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {30},
     number = {1},
     year = {1989},
     mrnumber = {1000828},
     zbl = {0668.03028},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1989__30_1_3_0/}
}