diff -r 6cb517754d8a -r 794c599cee53 slides/slides02.tex
--- a/slides/slides02.tex	Fri Apr 17 04:56:30 2015 +0100
+++ b/slides/slides02.tex	Fri May 01 19:19:31 2015 +0100
@@ -362,7 +362,7 @@
 expression that matches \bl{$s$}?\bigskip\bigskip\bigskip\bigskip
 
 \small
-\bl{$der\,c\,r$} gives the answer
+\bl{$der\,c\,r$} gives the answer, Brzozowski 1964
 \end{frame}}
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