@article{AA_2007_19_5_a8,
     author = {B. Plotkin and G. Zhitomirski},
     title = {Some logical invariants of algebras and logical relations between algebras},
     journal = {Algebra i analiz},
     pages = {214--245},
     publisher = {mathdoc},
     volume = {19},
     number = {5},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AA_2007_19_5_a8/}
}