AI approaches to the complexity of legal systems AICOL international workshops 2015-2017: AICOL-VI@JURIX 2015, AICOL-VII@EKAW 2016, AICOL-VIII@JURIX 2016, AICOL-IX@ICAIL 2017, and AICOL-X@JURIX 2017 : revised selected papers - Pagallo, Ugo (Springer, 2018)