Spin-symmetric solution of an interacting quantum dot attached to superconducting leads: Andreev states and the 0-π transitionVáclav Janiš, Vladislav Pokorný and Martin ŽondaEur. Phys. J. B, 89 9 (2016) 197DOI: https://doi.org/10.1140/epjb/e2016-70299-7