@article{UZKU_2011_153_3_a13,
     author = {I. Dymnikova},
     title = {The {Petrov} classification and vacuum dark fluid},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {154--164},
     publisher = {mathdoc},
     volume = {153},
     number = {3},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2011_153_3_a13/}
}