@article{TAC_2015_30_a5,
     author = {A.M. Cegarra and B.A. Heredia and J.Remedios},
     title = {Bicategorical homotopy pullbacks},
     journal = {Theory and applications of categories},
     pages = {147--205},
     publisher = {mathdoc},
     volume = {30},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2015_30_a5/}
}