The challenge of universal service in 21st century portugal R.C. Madureira Manuel De Oliveira Duarte R. Matias-Fonseca Publication Journal: IEEE Technology and Society Magazine Year of Publication: 2012 Volume: 31 Issue: 3 Pagination: 27-33 Identifiers Other Numbers: 2-s2.0-84867295176 Alternative titles DOIGoogle ScholarBibTeXRIS Locators