Karl Kunisch Ito, K., & Kunisch, K. (2011). KARUSH-KUHN-TUCKER CONDITIONS FOR NONSMOOTH MATHEMATICAL PROGRAMMING PROBLEMS IN FUNCTION SPACES. SIAM JOURNAL ON CONTROL AND OPTIMIZATION, 49(5), 2133–2154. https://doi.org/10.1137/100817061 Ito, K., & Kunisch, K. (2011). MINIMAL EFFORT PROBLEMS AND THEIR TREATMENT BY SEMISMOOTH NEWTON METHODS. SIAM JOURNAL ON CONTROL AND OPTIMIZATION, 49(5), 2083–2100. https://doi.org/10.1137/100784667 Ito, K., & Kunisch, K. (2010). Optimal control of parabolic variational inequalities. JOURNAL DE MATHEMATIQUES PURES ET APPLIQUEES, 93(4), 329–360. https://doi.org/10.1016/j.matpur.2009.10.005 Ito, K., & Kunisch, K. (2008). Semi-smooth Newton methods for the Signorini problem. APPLICATIONS OF MATHEMATICS, 53(5), 455–468. https://doi.org/10.1007/s10492-008-0036-7 Ito, K., & Kunisch, K. (2007). Optimal control of obstacle problems by H-1-obstacles. APPLIED MATHEMATICS AND OPTIMIZATION, 56(1), 1–17. https://doi.org/10.1007/s00245-007-0877-6 Ito, K., & Kunisch, K. (2004). The primal-dual active set method for nonlinear optimal control problems with bilateral constraints. SIAM JOURNAL ON CONTROL AND OPTIMIZATION, 43(1), 357–376. https://doi.org/10.1137/S0363012902411015 Ito, K., & Kunisch, K. (2003). Semi-smooth Newton methods for state-constrained optimal control problems. SYSTEMS & CONTROL LETTERS, 50(3), 221–228. https://doi.org/10.1016/s0167-6911(03)00156-7