Find below a list of some Reference managers to help in citations and bibliography
European center for the development of vocational training
Google Scholar helps you follow related research for key author and stand on the shoulder of giants
High-Energy Physics Literature Database
Turn even the largest set of documents into a fully searchable, easy-to-manage library. Read and annotate content via desktop client, browser or mobile app. Citation and bibliography creation is easy with thousands of styles to choose from.
Microsoft Academic semantic search provides you with highly relevant search results from continually refreshed and extensive academic content from over 120 million publications
System for Information on Grey Literature in Europe, is your open access to 700.000 bibliographical references of grey literature (paper) produced in Europe and allows you to export records and locate the documents.
Examples of grey (gray) literature include technical or research reports, doctoral dissertations, some conference papers, some official publications, and other types of grey literature.
OpenGrey covers Science, Technology, Biomedical Science, Economics, Social Science and Humanities.
Science.gov searches over 60 databases and over 2,200 scientific websites to provide users with access to more than 200 million pages of authoritative federal science information including research and development results.
Millions of research papers are available for free on government and university web servers, legally uploaded by the authors themselves, with the express permission of publishers.
Unpaywall automatically harvests these freely shared papers from thousands of legal institutional repositories, preprint servers, and publishers, making them all available to you as you read.
Unpaywall users are able to read over 52% of research papers for free--without having to pay money, fuss with a VPN, or use pirate sites like Sci-Hub. That's because we're built on a database of millions of open-access articles harvested from thousands of servers worldwide. When you browse to a paywalled paper, we check to see if we have a free copy. If we do, you'll see a green tab... just click, and read.
SSRN is devoted to the rapid worldwide dissemination of research and is composed of a number of specialized research networks.
WorldCat connects you to the collections and services of more than 10,000 libraries worldwide