PACS:92.10.Vz, 92.60.hh (all) DOI:10.1070/PU1960v003n01ABEH003263 URL: https://ufn.ru/en/articles/1960/1/g/ Citation: Brekhovskikh L "Propagation of acoustic and infrared waves in natural waveguides over long distances" Sov. Phys. Usp.3 159–166 (1960)