ADAMENKO, I.; KITSENKO, Y.; NEMCHENKO, K.; SLIPKO, V.; WYATT, A. Creation of high-energy phonons by four-phonon processes in anisotropic phonon systems of He II. ФІЗИКА НИЗЬКИХ ТЕМПЕРАТУР, Харків, Україна, v. 33, n. 5, p. 523–537, 2007. DOI: 10.1063/1.2737546. Disponível em: http://fnt.ilt.kharkov.ua/index.php/fnt/article/view/f33-0523e. Acesso em: 19 квіт. 2024.