@article{TAC_2003_11_a9,
     author = {A.M. Cegarra and A.R. Garzon},
     title = {Some algebraic applications of  graded categorical
group theory},
     journal = {Theory and applications of categories},
     pages = {215--251},
     publisher = {mathdoc},
     volume = {11},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2003_11_a9/}
}