Shilla distance-regular graphs

Brouwer, 1989

Coolsaet, 2005, A distance-regular graph with intersection array {21, 16, 8; 1, 4, 14} does not exist, European J. Combin., 26, 709, 10.1016/j.ejc.2004.04.005

Haemers, 1995, Interlacing eigenvalues and graphs, Linear Algebra Appl., 226/228, 593, 10.1016/0024-3795(95)00199-2

Jurisˇić, 2000, Nonexistence of some antipodal distance-regular graphs of diameter four, European J. Combin., 21, 1039, 10.1006/eujc.2000.0427