Journal of Historical Syntax, special issue (5) - Proceedings of the 20th Diachronic Generative Syntax (DiGS) Conference - Paola Crisma; Giuseppe Longobardi; Paola Crisma; Giuseppe Longobardi (Journal of Historical Syntax, special issue (5) - Proceedings of the 20th Diachronic Generative Syntax (DiGS) Conference, 2021)