@article{700733,
     title = {When categories of presheaves are binding},
     booktitle = {General Topology and its Relations to Modern Analysis and Algebra},
     series = {GDML\_Books},
     publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1972},
     pages = {447-450},
     mrnumber = {MR0364390},
     zbl = {0309.18003},
     url = {http://dml.mathdoc.fr/item/700733}
}

Trnková, V.; Reiterman, J. When categories of presheaves are binding, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1972), pp. 447-450. http://gdmltest.u-ga.fr/item/700733/