diff --git a/doc/developer/introduction.tex b/doc/developer/introduction.tex
index da42c41fc71489b48b2fcdfc17e2adeb108b57da..57ec7e7c439119dff1d909c0df671580b6b6380d 100644
--- a/doc/developer/introduction.tex
+++ b/doc/developer/introduction.tex
@@ -19,9 +19,8 @@ Section~\ref{doc:rules} for additional details about this
 documentation). 
 
 This guide introduces neither the use of \framac which is the purpose of the
-user manual~\cite{userman} and of the reference article~\cite{sefm12,fac15}, nor
-the 
-use of plug-ins which are documented in separated and dedicated
+user manual~\cite{userman} and of the reference articles~\cite{sefm12,fac15},
+nor the use of plug-ins which are documented in separated and dedicated
 manuals~\cite{slicing,wp,value,rte,aorai}.  We assume that the reader of this
 guide already read the \framac user manual and knows the main \framac concepts.