@article{CTGDC_2009__50_4_298_0,
     author = {Janelidze, Zurab},
     title = {Closedness properties of internal relations, {VI} : approximate operations},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     eid = {3},
     pages = {298--319},
     publisher = {Andr\'ee CHARLES EHRESMANN},
     volume = {50},
     number = {4},
     year = {2009},
     mrnumber = {2589620},
     zbl = {1188.18002},
     language = {en},
     url = {http://archive.numdam.org/item/CTGDC_2009__50_4_298_0/}
}