Collett, M. J.Kruglov, V. I.2004-12-032004-12-0320012001http://hdl.handle.net/2003/147110.17877/DE290R-11267enThe American Physical SocietyPhysical Review Letters530Roton Excitation Spectrum in Liquid Helium II10.1103/PhysRevLett.87.185302article (journal)