@article{TAC_2009_22_a19,
     author = {Mat{\'\i}as Menni},
     title = {Algebraic categories whose projectives are explicitly free},
     journal = {Theory and applications of categories},
     pages = {509--541},
     publisher = {mathdoc},
     volume = {22},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2009_22_a19/}
}