@article{TAC_2004_13_a0,
     author = {F. Borceux and J. Rosicky},
     title = {On von {Neumann} varieties},
     journal = {Theory and applications of categories},
     pages = {5--26},
     year = {2004},
     volume = {13},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2004_13_a0/}
}