@article{UZKU_2011_153_3_a8,
     author = {Z. Ahsan},
     title = {A study of the {Riemann} curvature tensor and {Petrov} classification in general relativity},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {87--93},
     publisher = {mathdoc},
     volume = {153},
     number = {3},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2011_153_3_a8/}
}