Nonlinear waves in continuous mediaEngelbrecht, JüriEncyclopedia of Continuum Mechanics2018 https://doi.org/10.1007/978-3-662-53605-6_235-1 Nonlinear waves in continuous mediaEngelbrecht, JüriEncyclopedia of Continuum Mechanics2020 https://doi.org/10.1007/978-3-662-55771-6_235