PubMed Central® (PMC) is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM)
"Also be sure to get your ebooks and literature not only without DRM, but also in a free format, preferably EPUB. While PDF is also free, it is less ideal for ebook viewing, reflowing, and editing. The sites listed provide files unencumbered, but it's important to be mindful that both of these can still contain DRM elsewhere."
cataloged freely available software for language tools, which includes the following: compilers, compiler generators, interpreters, translators, important libraries, assemblers, etc. -- things whose user interface is a language. Natural language processing tools may also be included.