Exact travelling wave solutions for four forms of nonlinear Klein-Gordon equations

A variable separated equation and its solutions are used to construct the exact travelling wave solutions for four forms of nonlinear Klein-Gordon equations. The solutions previously obtained by the tanh and sech method are recovered. New and more exact travelling wave solutions including solitons, kink and anti-kink, bell and anti-bell solitary wave solutions, periodic solutions, singular solutions and exponential solutions are found. (C) 2006 Elsevier B.V. All rights reserved.