N.G. Basova,
V.S. Letokhovb aLebedev Physical Institute, Russian Academy of Sciences, Leninsky prosp. 53, Moscow, 119991, Russian Federation bInstitute of Spectroscopy, Russian Academy of Sciences, ul. Fizicheskaya 5, Troitsk, Moscow, 108840, Russian Federation
PACS:06.30.Ft, 06.20.fb (all) DOI:10.1070/PU1969v011n06ABEH003779 URL: https://ufn.ru/en/articles/1969/6/e/ Citation: Basov N G, Letokhov V S "Optical frequency standards" Sov. Phys. Usp.11 855–880 (1969)