diff --git a/src/lang/README.md b/src/lang/README.md
index e23ec56..3106e98 100644
--- a/src/lang/README.md
+++ b/src/lang/README.md
@@ -10,7 +10,7 @@ All UNIX users will encounter a [shell](./shell.md) language, as it is typically
 
 The code samples from Kernighan's talks tend to use [C](./C.md) and [AWK](./awk.md).
 
- * 1974: [The Elements of Programming Style](https://archive.org/details/elementsofprogra00kernrich/mode/2up)
+ * 1974: [The Elements of Programming Style](https://archive.org/details/elementsofprogra00kernrich/mode/2up) ([PDF](http://www2.ing.unipi.it/~a009435/issw/extra/kp_elems_of_pgmng_sty.pdf)) ([2e PDF](https://seriouscomputerist.atariverse.com/media/pdf/book/Elements%20of%20Programming%20Style.pdf))
    * by Brian W. Kernighan and [Phillip James Plaugher](https://www.plauger.com/)
    * title refers to William Strunk's [The Elements of Style](https://www.gutenberg.org/ebooks/37134) (1918)
  * 1992: [Foundations of Computer Science](http://infolab.stanford.edu/%7Eullman/focs.html) ([TOC](http://infolab.stanford.edu/~ullman/focs/toc.pdf))
diff --git a/src/lang/regex.md b/src/lang/regex.md
index ba116e0..f40045f 100644
--- a/src/lang/regex.md
+++ b/src/lang/regex.md
@@ -11,7 +11,11 @@ Nevertheless, regular expressions are implemented in multiple programming langua
    * [IBM 7094 cheatsheet](https://swtch.com/~rsc/regexp/ibm7094.html)
  * 1987: [Structural Regular Expressions](http://doc.cat-v.org/bell_labs/structural_regexps/se.pdf)
    * by Rob Pike
- * 2003: [Regular-Expressions.info](https://www.regular-expressions.info/quickstart.html)
-   * by [Jan Goyvaerts](https://www.just-great-software.com/aboutjg.html)
  * 2007: [Implementing Regular Expressions](https://swtch.com/~rsc/regexp/) ([lecture](https://swtch.com/~rsc/talks/regexp.pdf))
    * by [Russ Cox](https://swtch.com/~rsc/)
+
+#### Other resources
+
+ * 2003: [Regular-Expressions.info](https://www.regular-expressions.info/quickstart.html)
+   * by [Jan Goyvaerts](https://www.just-great-software.com/aboutjg.html)
+ * [Regular expression tables on Wikipedia](https://en.wikipedia.org/wiki/Wikipedia:AutoWikiBrowser/Regular_expression)