Two relevant publications on the topic:
The German University Association for Advanced Graduate Training (UniWIND/GUAT) has published a booklet on Doctoral Supervision, with recommendations and examples of good practice. The booklet aims to serve both universities and individual doctoral supervisors.
It looks at responsibilities of the university and of the supervisor, gives good practice examples from Bielefeld and Berlin, and sketches the outline for a Workshop for Supervisors.
The University of Roviri I Virgili in Catalunya already last year published Good Practices In Doctoral Supervision. This document was the result of the “Tarragona Think Tank”, a follow up meeting to a EUA CDE workshop in 2016. The publication looks at doctoral supervision from a European as well as a local perspective and also stresses the importance of doctoral supervision as a competence that can’t be assumed present and needs to be trained, assessed and monitored.