There are two parts in this paper. Part I is concerned with the travelling wave solutions for reaction-diffusion-advection equations . We consider periodic advection and combustion, monostable nonlinear reaction term . We mainly survey the results of existence, uniqueness, and monotonicity of pulsating waves from the paper by Berestycki and Hamel [1]. Part II deals with exact travelling wave solutions of competitive Lotka-Volterra systems of three species.