@article{CTGDC_1988__29_1_9_0,
     author = {Betti, Renato and Grandis, Marco},
     title = {Complete theories in $2$-categories},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {9--57},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {29},
     number = {1},
     year = {1988},
     mrnumber = {941649},
     zbl = {0652.18001},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1988__29_1_9_0/}
}