1. Geodetic Graphs;Bosák,1978
2. Self-Centred Graphs;Capobianca,1979
3. On Moore graphs with diameter 2 and 3;Hoffman;IBM J. Res. Develop.,1960
4. K. R. Parthasarathy and N. Srinivasan, An extremal problem in geodetic graphs, revised version to be submitted to Discrete Math.