TY - JOUR AU - Philip R. Heath TI - Groupoid Operations and Fibre-Homotopy Equivalence. I. JO - Mathematische Zeitschrift PY - 1973 SP - 207 EP - 234 VL - 130 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/MZ_1973__130_171863/ ID - MZ_1973__130_171863 ER -