@article{01225047,
title = {Freeness conditions for 2-crossed modules and complexes.},
journal = {Theory and Applications of Categories [electronic only]},
volume = {4},
year = {1998},
pages = {174-194},
zbl = {0917.18004},
language = {en},
url = {http://dml.mathdoc.fr/item/01225047}
}
Mutlu, A.; Porter, T. Freeness conditions for 2-crossed modules and complexes.. Theory and Applications of Categories [electronic only], Tome 4 (1998) pp. 174-194. http://gdmltest.u-ga.fr/item/01225047/