@article{TAC_1998_4_a5,
     author = {Michael Barr},
     title = {The separated extensional {Chu} category},
     journal = {Theory and applications of categories},
     pages = {137--147},
     year = {1998},
     volume = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_1998_4_a5/}
}