https://thepalaceproject.org/app/ (find my library選擇California's Bookshelf)
https://www.overdrive.com/
https://centslessbooks.com/
https://www.gutenberg.org/
https://manybooks.net/
https://www.feedbooks.com/
https://www.pdfbooksworld.com/
https://openlibrary.org/
https://www.free-ebooks.net/

專業書籍：
http://gen.lib.rus.ec/

兒童書：
http://en.childrenslibrary.org/