@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/