@article{1255630887,
author = {Heller, Alex},
title = {Homotopy invariants of chain complexes},
journal = {Illinois J. Math.},
volume = {5},
number = {1},
year = {1961},
pages = { 420-424},
language = {en},
url = {http://dml.mathdoc.fr/item/1255630887}
}
Heller, Alex. Homotopy invariants of chain complexes. Illinois J. Math., Tome 5 (1961) no. 1, pp. 420-424. http://gdmltest.u-ga.fr/item/1255630887/