1. Aronson, D.G.: The asymptotic speed of propagation of a simple epidemic. In: Nonlinear Diffusion (NSF-CBMS Regional Conference on Nonlinear Diffusion Equations, University of Houston, Houston, TX, 1976). Research Notes in Mathematics, vol. 14, pp. 1–23. Pitman, London (1977)
2. Aronson, D.G., Weinberger, H.F.: Nonlinear diffusion in population genetics, combustion, and nerve pulse propagation. In: Partial Differential Equations and Related Topics (Program, Tulane University, New Orleans, LA, 1974). Lecture Notes in Mathematics, vol. 446, pp. 5–49. Springer, Berlin (1975)
3. Aronson D.G., Weinberger H.F.: Multidimensional nonlinear diffusion arising in population genetics. Adv. Math. 30(1), 33–76 (1978)
4. Bunting, G., Du, Y., Krakowski, K.: Spreading speed revisited: analysis of a free boundary model. Preprint (2011)
5. Cantrell R.S., Cosner C.: Spatial Ecology via Reaction-Diffusion Equations. Wiley, Chichester (2003)