diff -r a697421eaa04 -r 598741d39d21 handouts/scala-ho.tex
--- a/handouts/scala-ho.tex	Fri Apr 28 11:01:25 2017 +0100
+++ b/handouts/scala-ho.tex	Sun May 07 00:20:58 2017 +0100
@@ -982,6 +982,12 @@
 inherited from the JVM that can be really annoying. For
 example a fixed stack size. One can work around this
 particular limitation, but why does one have to?
+More such `puzzles' can be found at
+
+\begin{center}
+  \url{http://scalapuzzlers.com} and
+  \url{http://latkin.org/blog/2017/05/02/when-the-scala-compiler-doesnt-help/}
+\end{center}
 
 Even if Scala has been a success in several high-profile
 companies, there is also a company (Yammer) that first used