The simplest equation method has been used for finding the exact solutions of coupled sine-Gordon equations. Such equations have some useful applications in physics and biology, so finding their exact solutions is of great importance.
"Exact Solutions of Coupled Sine-Gordon Equations Using the Simplest Equation Method." J. Appl. Math. 2014 1 - 5, 2014. https://doi.org/10.1155/2014/534346