trlib: a vector-free implementation of the GLTR method for iterative solution of the trust region problem. - Felix Lenders; Christian Kirches; Andreas Potschka (Optim. Methods Softw., 2018)

Approximation Properties and Tight Bounds for Constrained Mixed-Integer Optimal Control. - Christian Kirches; Felix Lenders; Paul Manns (SIAM J. Control. Optim., 2020)

Approximation properties of sum-up rounding in the presence of vanishing constraints. - Paul Manns; Christian Kirches; Felix Lenders (Math. Comput., 2021)