@article{701183,
     title = {Realizing homomorphisms of category algebras},
     booktitle = {Abstracta. 8th Winter School on Abstract Analysis},
     series = {GDML\_Books},
     publisher = {Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1980},
     pages = {86-89},
     url = {http://dml.mathdoc.fr/item/701183}
}

Graf, Siegfried. Realizing homomorphisms of category algebras, dans Abstracta. 8th Winter School on Abstract Analysis, GDML_Books,  (1980), pp. 86-89. http://gdmltest.u-ga.fr/item/701183/