@article{COMIM_2000_8_1_a9,
     author = {Fajmon, B\v{r}etislav},
     title = {Operations, homomorphism and update versus relational database systems},
     journal = {Communications in Mathematics},
     pages = {99--109},
     year = {2000},
     volume = {8},
     number = {1},
     mrnumber = {1800226},
     zbl = {1024.08001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/COMIM_2000_8_1_a9/}
}