V.M. Agranovich Institute of Spectroscopy, Russian Academy of Sciences, ul. Fizicheskaya 5, Troitsk, Moscow, 108840, Russian Federation
PACS:71.35.−y, 78.20.−e () DOI: URL: https://ufn.ru/en/articles/1963/6/k/ Citation: Agranovich V M "Letter to the Editor" Sov. Phys. Usp.5 1032–1032 (1963)