A General Approach of Quasi-Exactly Solvable Schroedinger Equations with   Three Known Eigenstates
  We propose a general method for constructing quasi-exactly solvable potentials with three analytic eigenstates. These potentials can be real or complex functions but the spectrum is real. A comparison with other methods is also performed. 
N. Debergh, J. Ndimubandi, B. Van den Bossche