Update free-science-books.md

[ankitpriyadarshii]

What does this PR do?

Add Resource(s) | Remove Resource(s) | Add info | Improve Repo

For resources

Description

Why is this valuable (or not)

How do we know it's really free?

For book lists, is it a book?

Checklist:

• [x] Not a duplicate
• [x] Included author(s) if appropriate
• [x] Lists are in alphabetical order
• [x] Needed indications added (PDF, access notes, under construction)

[eshellman]

The links you have provided are not authorized distributions. We do not accept such links because

• unauthorized distributions don't last long
• unauthorized distributions jeopardize our repo with respect to copyright takedowns
• we want to promote books that are really free by the intent of the creator