DATABASES:
arXiv (arXiv is owned and operated by Cornell University. Open access to 1,533,444 e-prints in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.)
Front for the arXiv (The Front for the arXiv is an overlay maintained at UC Davis by Greg Kuperberg. It was started in 1998 as a front end for the mathematics section of the arXiv and some find it easier to use.)
Astrophysics Data System (ADS) (A digital library portal for researchers in astronomy and physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant.)
CiteSeerX (CiteSeerx is an evolving open access scientific literature digital library and search engine that has focused primarily on the literature in computer and information science. CiteSeerx attempts to provide resources such as algorithms, data, metadata, services, techniques, and software that can be used to promote other digital libraries.)
EUR-Lex (Free access to EU law, Official Journal of the European Union and other public documents)
European Commission (Search for European Commission planning and strategy documents, factsheets, studies, tender opportunities and other official notices in EU regional and urban development, business and economy. Find EU laws, statistics and public opinion documents.)
Google Scholar (Academic literature search across disciplines and sources.)
Networked Digital Library of Theses and Dissertations (NDLTD) (NDLTD provides information and a search engine for electronic theses and dissertations (ETDs), whether they are open access or not.)
Hathi Trust Digital Library (HathiTrust is a partnership of academic & research institutions, offering a collection of millions of titles digitized from libraries around the world.)
International Development Research Centre Digital Library (IDRC) (The IDRC Digital Library is an open access repository of research results and documents generated by IDRC-funded projects, IDRC funding recipients, and IDRC staff. It represents the tangible intellectual output of IDRC’s mandate.)
OECD iLibrary (The online library of the Organisation for Economic Cooperation and Development (OECD) featuring its books, papers and statistics and is the gateway to OECD’s analysis and data. All book and journal content is available to all users to read online by clicking the READ icon.)
Open Access Library (Search engine for and access tool to millions of free academic articles in all subject and in all languages (as long as the article has an English title and abstract).)
Open Access Theses and Dissertations (Search engine and access tool to millions of graduate theses and dissertations published around the world.)
OpenDOAR: Directory of Open Access Repositories (OpenDOAR is the quality-assured global directory of academic open access repositories.)
Publications Office of the European Union (Free and priced publications of the EU institutions in economics, finance, geography, production, trade, etc.)
RePEc: Research Papers in Economics (A collaborative effort of volunteers in over 80 countries to enhance the dissemination of research in economics. The heart of the project is a database of working papers, journal articles, and software components, all downloadable for free. Coverage: 1993-)
Social Science Research Network (SSRN) (An open-access online preprint community providing valuable services to leading academic schools and government institutions. Specializing primarily in social sciences, including economics, law, corporate governance, and humanities, SSRN is branching out into other science disciplines providing opportunities for scholars to post their early research, collaborate on theories and discoveries, and get credit for their ideas before peer reviewed publication.)
United Nations Conference on Trade and Development (UNCTAD) (Provides authoritative data and analysis on trade, investment, finance and technology)
Wolfram MathWorld (The web’s most extensive mathematical resource, provided as a free service to the world’s mathematics and internet communities as part of a commitment to education and educational outreach by Wolfram Research, makers of Mathematica.)
E-BOOKS:
Internet Archive (A non-profit, digital library of Internet sites and other cultural artifacts in digital form.)
DOAB (Directory of open access books)
OTHER LIBRARY CATALOGS:
University of L’Aquila, Library
INFN Gran Sasso National Laboratory, Library
Sant’Anna School for Advanced Studies, Library / Pisa
Scuola Normale Superiore, Library
Italian National Library Service (SBN)
UN Library Catalog (Includes subject guides)
REFERENCE SOURCES:
The Review of Particle Physics (2019) (M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) and 2019 update.)
FOLDOC (Free Online Dictionary of Computing)
Webopedia (Online Tech Dictionary for Students, Educators and IT Professionals)