Quantum Monte Carlo impurity solvers for multi-orbital problems and frequency-dependent interactionsH. Shinaoka, F. Assaad, N. Blümer and P. WernerEur. Phys. J. Special Topics, 226 11 (2017) 2499-2523DOI: https://doi.org/10.1140/epjst/e2017-70050-x