This paper contains the printed version of the concluding remarks I gave at the Conference XII Multifrequency Behaviour of High Energy Cosmic Sources Workshop, 12--17 June, 2017 in
Palermo, Italy
Metadata are provided both in article format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in proceeding format which is more detailed and complete.
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.