“…Indeed, the optimal order of convergence of the eigenvalues is O( u − u h 2 m,Ω ), where u is the corresponding exact eigenfunction. Obviously u − u h 2 0,Ω has higher order of accuracy and, moreover, it is easy to obtain the same high order of convergence for w − w h 2 m,Ω (see [2], [3], [29], [36]). Now, we will present the final step of our idea described as nonconformingconforming approach to eigenvalues approximation.…”