@article{TAC_2018_33_a4,
     author = {Michael Shulman},
     title = {Contravariance through enrichment},
     journal = {Theory and applications of categories},
     pages = {95--130},
     publisher = {mathdoc},
     volume = {33},
     year = {2018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2018_33_a4/}
}