@article{TAC_2009_22_a7,
     author = {Ronald Brown and Rafael Sivera},
     title = {Algebraic colimit calculations in homotopy theory using fibred and cofibred categories},
     journal = {Theory and applications of categories},
     pages = {222--251},
     publisher = {mathdoc},
     volume = {22},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2009_22_a7/}
}