@article{CTGDC_1995__36_4_323_0,
     author = {Sousa, Lurdes},
     title = {Orthogonality and closure operators},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {323--343},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {36},
     number = {4},
     year = {1995},
     mrnumber = {1367590},
     zbl = {0842.18001},
     language = {en},
     url = {http://archive.numdam.org/item/CTGDC_1995__36_4_323_0/}
}