diff --git a/books/free-programming-books-subjects.md b/books/free-programming-books-subjects.md
index 8648f4cce..8ffd482bc 100644
--- a/books/free-programming-books-subjects.md
+++ b/books/free-programming-books-subjects.md
@@ -192,12 +192,12 @@ Books that cover a specific programming language can be found in the  [BY PROGRA
 
 * [An Introduction to GCC](https://web.archive.org/web/20170326232435/http://www.network-theory.co.uk/docs/gccintro/index.html) - Brian Gough
 * [Basics of Compiler Design (Anniversary Edition)](http://www.diku.dk/~torbenm/Basics/) - Torben Mogensen
-* [Compiler Design in C (1990)](http://www.holub.com/software/compiler.design.in.c.html) - Allen Holub, Prentice Hall
+* [Compiler Design in C (1990)](https://holub.com/goodies/compiler/compilerDesignInC.pdf) - Allen Holub, Prentice Hall (PDF)
 * [Compiler Design: Theory, Tools, and Examples, C/C++ Edition](http://elvis.rowan.edu/~bergmann/books/Compiler_Design/c_cpp/Text/C_CppEd.pdf) - Seth D. Bergmann (PDF)
 * [Compiler Design: Theory, Tools, and Examples, Java Edition](http://elvis.rowan.edu/~bergmann/books/Compiler_Design/java/CompilerDesignBook.pdf) - Seth D. Bergmann (PDF)
 * [Compiling Scala for the Java Virtual Machine](http://lampwww.epfl.ch/~schinz/thesis-final-A4.pdf) - Michel Schinz (PDF)
 * [Compiling Techniques (1969)](http://www.chilton-computing.org.uk/acl/literature/books/compilingtechniques/overview.htm) - F.R.A. Hopgood, Macdonald
-* [Crafting Interpreters](http://www.craftinginterpreters.com) - Bob Nystrom (HTML)
+* [Crafting Interpreters](http://www.craftinginterpreters.com/contents.html) - Bob Nystrom (HTML)
 * [EXPL NITC: Build your own Compiler](https://silcnitc.github.io) - Murali Krishnan K., students in the Department of Computer Science and Engineering of the Calicut National Institute of Technology (HTML)
 * [Implementing Functional Languages: A Tutorial](http://research.microsoft.com/en-us/um/people/simonpj/Papers/pj-lester-book/) - Simon Peyton Jones, David Lester
 * [Introduction to Compilers and Language Design](https://www3.nd.edu/~dthain/compilerbook/compilerbook.pdf) - Douglas Thain (PDF)