Kaelberer, FelixPolthier, KonradReitebuch, UlrichWardetzky, Max2015-02-202015-02-2020051467-8659https://doi.org/10.1111/j.1467-8659.2005.00872.xFreeLence - Coding with Free Valences10.1111/j.1467-8659.2005.00872.x469-478