diff --git a/content/posts/books.md b/content/posts/books.md
index 6dbb538..c7f1fe7 100644
--- a/content/posts/books.md
+++ b/content/posts/books.md
@@ -4,7 +4,9 @@ date = 2024-01-29T21:56:49+01:00
 draft = false
 +++
 
-This is just a collection, in so specific order, of books i read or i intent to read in the future. The all are related to the world of programming, hacking, FOOS, Linux and software in general. 
+This is just a collection, in so specific order, of books i read or i intent to read in the future. The all are related to the world of programming, hacking, FOOS, Linux and software in general.
+
+the [F] tag means that the book is available freely online. A great starting point if you want to look for books that are free on the topic of programming, computer vision, mathematics and much more is [this amazing repository](https://github.com/EbookFoundation/free-programming-books)
 
 # Programming
 - Clean Code 
@@ -16,7 +18,8 @@ This is just a collection, in so specific order, of books i read or i intent to
 
 # Open Source/ Free software
 - La cattedrale e il bazaar
-- Open non e' Free
+- Open non e' Free [F]
 
 # Linux
+- The Orange book pt. 2 [F]
 - [How Linux Works, 3rd Edition: What Every Superuser Should Know](https://nostarch.com/howlinuxworks3)