@article{CTGDC_1987__28_3_183_0,
     author = {Hardie, K. A. and Kamps, K. H.},
     title = {Homotopy over $B$ and under $A$},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {183--196},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {28},
     number = {3},
     year = {1987},
     mrnumber = {923628},
     zbl = {0648.55010},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1987__28_3_183_0/}
}