@article{UZKU_2011_153_3_a15,
     author = {G. Hall},
     title = {Some developments of {Petrov's} work on conformal and projective structure},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {175--184},
     publisher = {mathdoc},
     volume = {153},
     number = {3},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2011_153_3_a15/}
}