@article{CTGDC_1985__26_1_43_0,
     author = {Pitts, Andrews},
     title = {On product and change of base for toposes},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {43--61},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {26},
     number = {1},
     year = {1985},
     zbl = {0574.18003},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1985__26_1_43_0/}
}