@article{TAC_2004_12_a0,
     author = {T. Everaert and T. Van der Linden},
     title = {Baer invariants in semi-abelian categories {I:} {General} theory},
     journal = {Theory and applications of categories},
     pages = {1--33},
     publisher = {mathdoc},
     volume = {12},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2004_12_a0/}
}