@article{GDZPPN002061309, title = {Almost Canonical Inverse Images}, journal = {Commentarii mathematici Helvetici}, volume = {49}, year = {1974}, pages = {168-174}, zbl = {0318.57014}, url = {http://dml.mathdoc.fr/item/GDZPPN002061309} }
Quinn, Frank. Almost Canonical Inverse Images. Commentarii mathematici Helvetici, Tome 49 (1974) pp. 168-174. http://gdmltest.u-ga.fr/item/GDZPPN002061309/