See also: D.S. Ponomarev, D.V. Lavrukhin, I.E. Spektor, K.I. Zaytsev, R.A. Khabibullin, V.N. Kurlov, V.V. Kveder, A.E. Yachmenev
PACS: 07.57.-c, 42.30.Wb, 84.40.-x