Ultrahigh resolution spectroscopy based on wave competition in a ring laser Belenov, E. M. ; Danileǐko, M. V. ; Kozubovskiǐ, V. R. ; Nedavniǐ, A. P. ; Shpak, M. T. Abstract Publication: Soviet Journal of Experimental and Theoretical Physics Pub Date: July 1976 Bibcode: 1976JETP...44...40B