Davtyan, N.N., and R.R. Kamalian. “SOME RELATIONS BETWEEN THE μ-PARAMETERS OF REGULAR GRAPHS”. Proceedings of the YSU A: Physical and Mathematical Sciences, vol. 49, no. 1 (236), Mar. 2015, pp. 47-51, https://doi.org/10.46991/PYSUA.2015.49.1.047.