@article{CTGDC_2006__47_1_50_0,
     author = {Niefield, Susan},
     title = {Homotopic pullbacks, {Lax} pullbacks, and exponentiability},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {50--80},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {47},
     number = {1},
     year = {2006},
     mrnumber = {2220061},
     zbl = {1095.18001},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_2006__47_1_50_0/}
}