@article{GDZPPN002441934,
title = {Crossed squares and combinatorical homotopy.},
journal = {Mathematische Zeitschrift},
volume = {212},
year = {1993},
pages = {93-110},
zbl = {0789.55008},
url = {http://dml.mathdoc.fr/item/GDZPPN002441934}
}
Ellis, Graham. Crossed squares and combinatorical homotopy.. Mathematische Zeitschrift, Tome 212 (1993) pp. 93-110. http://gdmltest.u-ga.fr/item/GDZPPN002441934/