@article{GDZPPN00240849X, title = {Obstruction Theory in Fiber Spaces.}, journal = {Mathematische Zeitschrift}, volume = {121}, year = {1971}, pages = {1-17}, zbl = {0222.55023}, url = {http://dml.mathdoc.fr/item/GDZPPN00240849X} }
McClendon, James F. Obstruction Theory in Fiber Spaces.. Mathematische Zeitschrift, Tome 121 (1971) pp. 1-17. http://gdmltest.u-ga.fr/item/GDZPPN00240849X/