参考文献:1. A. A. Makhnev, Diskret. Mat. 10(2), 72鈥?6 (1998). 2. A. A. Makhnev and D. V. Paduchikh, Diskret. Mat. 13(3), 91鈥?09 (2001). 3. A. A. Makhnev, D. V. Paduchikh, and M. M. Khamgokova, Dokl. Math. 82, 773鈥?76 (2010). CrossRef 4. P. Cameron, D. R. Hughes, and A. Pasini, Geom. Dedic. 35, 193鈥?28 (1990). CrossRef 5. A. E. Brouwer and W. H. Haemers, http://www.win.tue.nl/aeb/ 6. A. A. Makhnev, Math. Notes 68, 232鈥?36 (2000). CrossRef 7. A. A. Makhnev, Sib. Math. J. 49, 130鈥?46 (2008). CrossRef
作者单位:A. A. Makhnev (1) D. V. Paduchikh (1)
1. Institute of Mathematics and Mechanics, Ural Branch, Russian Academy of Sciences, ul. S. Kovalevskoi 16, Yekaterinburg, 620990, Russia