J. Giesselmann, and T. Pryer. Finite Volumes for Complex Applications VIII - Methods and Theoretical Aspects, volume 199 of Springer Proceedings in Mathematics & Statistics, page 457-466. Springer, (2017)
M. Gugat, M. Herty, A. Klar, G. Leugering, and V. Schleper. Constrained optimization and optimal control for partial differential equations, volume 160 of International series of numerical mathematics, page 123-146. Birkhäuser, (2012)