On Periodic Solutions Of Lienard Equations
  We Prove That The Uniform Upper Bound for the Number Of Limit Cycles Of The Lienard Equation of Degree 4 Can be equals to 2. Further We Suggest to Embedding Planar Lienard Equations In Higher Dimension and Present question of completly integrabiolity of Corresponding Hamiltonians. Actually this Question Suggest To Look at to Limit Cycles Problems with KAM methods 
Ali Taghavi