Transfer of the bryson-denham-dreyfus approach for state-constrained ODE optimal control problems to elliptic optimal control problems. - Michael Frey; Simon Bechmann; Armin Rund; Hans Josef Pesch (MMAR, 2011)

Bang-bang and singular controls in optimal control problems with partial differential equations. - Hans Josef Pesch; Simon Bechmann; Jan-Eric Wurst (CDC, 2012)