A better method to determine the stability region of an L-stable   implicit-explicit Runge-Kutta scheme
  We propose a better method to determine the stability region of an L-stable implicit-explicit Runge-Kutta scheme. This method always provides the correct result, while other methods sometimes give wrong result. It is useful in the analysis for implicit-explicit Runge-Kutta schemes.   Keywords: Stability region, Implicit-explicit (IMEX) scheme 
Shu-Chao Duan
math.NA