@article{TM_2014_286_a2,
     author = {A. Biggs and H. M. Khudaverdian},
     title = {Operator pencils on the algebra of densities},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {40--64},
     publisher = {mathdoc},
     volume = {286},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_2014_286_a2/}
}