1. Elliptic semiplanes I: existence and classification;Baker;Proc. 8th S.E. Conf. on Combinatorics, Graph Theory and Computing,1977
2. V. Batagelj (talk in Malta, June 1990).
3. On regular packings and coverings;Bermond;Ann. Discrete Math.,1987
4. Graphs with even girth and small excess;Biggs;Math. Proc. Cambridge Philos. Soc.,1980
5. Hyperbolic graphs from hyperbolic planes;DiPaola;Congr. Numer.,1989