@article{SM_1991_68_2_a11,
     author = {M. V. Sapir},
     title = {A minimal variety of associative algebras with unsolvable word problem},
     journal = {Sbornik. Mathematics},
     pages = {567--584},
     publisher = {mathdoc},
     volume = {68},
     number = {2},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1991_68_2_a11/}
}