Delocalized nonlinear vibrational modes in graphene: second harmonic generation and negative pressure / E. A. Korznikova, S. A. Shcherbinin, D. S. Ryabov [et al.] // Physica status solidi B. 2019. Vol. 256, № 1. P. 1800061 (1-7). URL: http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000660409