A virtual control concept for state constrained optimal control problems. - Klaus Krumbiegel; Arnd Rösch (Comput. Optim. Appl., 2009)

A Priori Error Analysis for Linear Quadratic Elliptic Neumann Boundary Control Problems with Control and State Constraints. - Klaus Krumbiegel; Christian Meyer 001; Arnd Rösch (SIAM J. Control. Optim., 2010)

Regularization for semilinear elliptic optimal control problems with pointwise state and control constraints. - Klaus Krumbiegel; Ira Neitzel; Arnd Rösch (Comput. Optim. Appl., 2012)

Second Order Sufficient Optimality Conditions for Parabolic Optimal Control Problems with Pointwise State Constraints. - Klaus Krumbiegel; Joachim Rehberg (SIAM J. Control. Optim., 2013)

Superconvergence for Neumann boundary control problems governed by semilinear elliptic equations. - Klaus Krumbiegel; Johannes Pfefferer (Comput. Optim. Appl., 2015)