text: * L.I. Mandelstam, Zh. Russ. Fiz-Khim., Ova. 58, 381 (1926).
  *B.Ya. Zel’dovich, V.I.Popovichev, V.V.Ragulskii and F.S.Faisullov, "Connection between the wavefronts of the reflected and exciting light in stimulated Mandel’shtam Brillouin scattering," Sov. Phys. JETP, 15, 109 (1972)