Most of the links listed on this page offer resources with a less restrictive copyright licence under open access or creative commons rules.
What are Open Access Resources?
Open access resources are publications that have "free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, [allow search engines to] crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other then those inseparable from gaining access to the internet itself". (Budapest Open Access Initiative)