@article{ZNSL_2000_267_a14,
     author = {S. V. Matveev and M. A. Ovchinnikov and M. V. Sokolov},
     title = {Construction and properties of the $t$-invariant},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {207--219},
     year = {2000},
     volume = {267},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2000_267_a14/}
}