https://github.com/vhf/free-programming-books

http://www.oreilly.com/programming/free/

https://97-things-every-x-should-know.gitbooks.io/97-things-every-programmer-should-know/content/en/index.html

https://dev.to/brogrammer2018/free-programming-books-updated-4pdp

https://www.vice.com/en_us/article/kz4e3e/millions-of-books-are-secretly-in-the-public-domain-you-can-download-them-free

程序员必备的 10 大 GitHub 仓库 - https://www.infoq.cn/article/PPBgMwCeovtabDxABwIe https://medium.com/javascript-in-plain-english/10-essential-github-repos-for-software-developers-6a42ebba279

Books that every engineering manager should read - https://medium.com/free-code-camp/books-that-every-engineering-manager-should-read-7a053e296d11

Australian National University press - https://press.anu.edu.au/publications?sort=score

30 free ebooks for developers - https://dev.to/pascavld/30-free-ebooks-for-all-developers-30pf

If You Want To Excel At Math, Read These 20 Books - https://www.cantorsparadise.com/if-you-want-to-excel-at-math-read-these-20-books-83748ae17dfc