@article{CTGDC_1985__26_1_3_0,
     author = {Hardie, K. A. and Kamps, K. H.},
     title = {Exact sequence interlocking and free homotopy theory},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {3--31},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {26},
     number = {1},
     year = {1985},
     mrnumber = {794414},
     zbl = {0574.55012},
     language = {en},
     url = {http://archive.numdam.org/item/CTGDC_1985__26_1_3_0/}
}