@article{TAC_2019_34_a27,
     author = {J. R. A. Gray},
     title = {On spans with right fibred right adjoints},
     journal = {Theory and applications of categories},
     pages = {854--882},
     publisher = {mathdoc},
     volume = {34},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2019_34_a27/}
}