@article{SM_2001_192_4_a3,
     author = {D. N. Ivanov},
     title = {On balanced systems of idempotents},
     journal = {Sbornik. Mathematics},
     pages = {551--564},
     publisher = {mathdoc},
     volume = {192},
     number = {4},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2001_192_4_a3/}
}