AUTHOR=Ulgiati Sergio , Zucaro Amalia TITLE=Challenges in Urban Metabolism: Sustainability and Well-Being in Cities JOURNAL=Frontiers in Sustainable Cities VOLUME=1 YEAR=2019 URL=https://www.frontiersin.org/journals/sustainable-cities/articles/10.3389/frsc.2019.00001 DOI=10.3389/frsc.2019.00001 ISSN=2624-9634