1. C. Truesdell, W. Noll: “The Nonlinear Field Theories of Mechanics”, in Encyclopedia of Physics Vol. 3/3, (Springer, Berlin, Heidelberg, New York 1965)
2. G.B. Whitham: Linear and Nonlinear Waves (Wiley, New York 1974)
3. D.S. Chandrasekharaiah: Appl. Mech. Rev., 39, 355–376 (1986)
4. A.N. Kolmogorov, I.G. Petrovsky, N.S. Piscounov: Bull. Univ. Etat Moscow, A116, 1–25 (1937)
5. R.A. Fisher: Ann. Eugenics, 7, 355–369 (1938)