1. Four boundary value problems for the Cauchy–Riemann equation in a quarter plane;Abdymanapov,2009
2. Boundary value problems for complex elliptic partial differential equations of higher orders;Akel,1996
3. A Riemann–Hilbert boundary value problem in a bounded sector;Akel;Complex Var. Elliptic Equ.,2014
4. On nonlinear Riemann–Hilbert boundary value problems for second order elliptic systems in the plane;Akel;Appl. Anal.,1996
5. On the Pompeiu operator of higher order and applications;Akel;Complex Variables Theory Appl.,1997