Pullback and pushout squares in a special double category with connection
Cahiers de Topologie et Géométrie Différentielle Catégoriques, Volume 24 (1983) no. 2, p. 161-192
@article{CTGDC_1983__24_2_161_0,
     author = {Spencer, Christopher B. and Wong, Y. L.},
     title = {Pullback and pushout squares in a special double category with connection},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {24},
     number = {2},
     year = {1983},
     pages = {161-192},
     zbl = {0519.18008},
     mrnumber = {710039},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1983__24_2_161_0}
}
Spencer, C. B.; Wong, Y. L. Pullback and pushout squares in a special double category with connection. Cahiers de Topologie et Géométrie Différentielle Catégoriques, Volume 24 (1983) no. 2, pp. 161-192. http://www.numdam.org/item/CTGDC_1983__24_2_161_0/

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