Are there scale economies in urban waste and wastewater municipal services? A non-radial input-oriented model applied to the Portuguese local government Journal of Cleaner Production Journal Article Paulo Caldas Diogo Ferreira Brian Dollery Rui Marques Publication Year of Publication: 2019 Volume: 219 Pagination: 531--539 Identifiers ISSN: 0959-6526 Other Numbers: cv-prod-id-1256448 Locators DOI: 10.1016/j.jclepro.2019.02.076 Sustainable Development Goals