diff --git a/books/free-programming-books-subjects.md b/books/free-programming-books-subjects.md
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--- a/books/free-programming-books-subjects.md
+++ b/books/free-programming-books-subjects.md
@@ -842,9 +842,9 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Introduction to Computer Science](https://www.cse.iitd.ernet.in/~suban/CSL102/) - Subhashis Banerjee, IIT Delhi
 * [Introduction to Computing](https://www.computingbook.org) - David Evans
 * [Principled Programming / Introduction to Coding in Any Imperative Language](https://www.cs.cornell.edu/info/people/tt/Principled_Programming.html) - Tim Teitelbaum
-* [Programming and Programming Languages](https://papl.cs.brown.edu/2019/) - Shriram Krishnamurthi
-* [Programming Languages: Application and Interpretation (2nd Edition)](https://cs.brown.edu/~sk/Publications/Books/ProgLangs/) - Shriram Krishnamurthi
-* [Programming Languages: Application and Interpretation (3rd Edition)](https://www.plai.org/3/5/plai-v325.pdf) - Shiriram Krishnamurthi (PDF)
+* [Programming and Programming Languages](https://papl.cs.brown.edu/2019/) - Shriram Krishnamurthi (PDF)
+* [Programming Languages: Application and Interpretation (2nd Edition)](https://cs.brown.edu/~sk/Publications/Books/ProgLangs/) - Shriram Krishnamurthi (HTML, PDF)
+* [Programming Languages: Application and Interpretation (3rd Edition)](https://www.plai.org/3/5/plai-v325.pdf) - Shiriram Krishnamurthi (PDF) (CC BY-NC-SA)
 * [Structure and Interpretation of Computer Programs](https://web.mit.edu/6.001/6.037/sicp.pdf) - Harold Abelson, Gerald Jay Sussman, Julie Sussman (PDF) (CC BY-SA)
 * [Structure and Interpretation of Computer Programs](https://sarabander.github.io/sicp/html/index.xhtml) - Harold Abelson, Gerald Jay Sussman, Julie Sussman (HTML) (CC BY-SA)
 * [The Black Art of Programming](http://self.gutenberg.org/wplbn0002828847-the-black-art-of-programming-by-mcilroy-mark.aspx?) - Mark McIlroy