“…Other methods exist to solve this problem. The main methods are Tikhonov like methods, [8], [11], [17], [18], quasi reversibility methods [3], [9], [13], [15], and iterative methods [1], [12], [14], [16]. Quasi reversibility methods and Tikhonov regularization methods present the avantage to lead to well-posed problems after modifying the partial derivative operator.…”