@article{GDZPPN002425785, title = {Counting Elemnts in Homotopy Sets.}, journal = {Mathematische Zeitschrift}, volume = {177}, year = {1981}, pages = {527-554}, zbl = {0498.55006}, url = {http://dml.mathdoc.fr/item/GDZPPN002425785} }
Switzer, Robert. Counting Elemnts in Homotopy Sets.. Mathematische Zeitschrift, Tome 177 (1981) pp. 527-554. http://gdmltest.u-ga.fr/item/GDZPPN002425785/