@article{1256049410,
author = {Dror, E. and Dwyer, W. G. and Kan, D. M.},
title = {An arithmetic square for virtually nilpotent spaces},
journal = {Illinois J. Math.},
volume = {21},
number = {4},
year = {1977},
pages = { 242-254},
language = {en},
url = {http://dml.mathdoc.fr/item/1256049410}
}
Dror, E.; Dwyer, W. G.; Kan, D. M. An arithmetic square for virtually nilpotent spaces. Illinois J. Math., Tome 21 (1977) no. 4, pp. 242-254. http://gdmltest.u-ga.fr/item/1256049410/