@article{TAC_2006_16_a4,
     author = {Colin McLarty},
     title = {Every {Grothendieck} topos has a one-way site},
     journal = {Theory and applications of categories},
     pages = {123--126},
     publisher = {mathdoc},
     volume = {16},
     year = {2006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2006_16_a4/}
}