@article{TAC_2012_26_a2,
     author = {George M. Bergman},
     title = {On diagram-chasing in double complexes},
     journal = {Theory and applications of categories},
     pages = {60--96},
     publisher = {mathdoc},
     volume = {26},
     year = {2012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2012_26_a2/}
}