1. A. Fukshansky and G. Stroth, Semiclassical parabolic systems related to M24, Geom. Dedicata 70 (1998), no. 3, 305–329.[MR]
  2. Anna Fukshansky and Corinna Wiedorn, C-extensions of the Petersen geometry for M22, European J. Combin. 20 (1999), no. 3, 233–238.[MR]