diff --git a/Doc/ref/ref2.tex b/Doc/ref/ref2.tex
index 3319949..4947650 100644
--- a/Doc/ref/ref2.tex
+++ b/Doc/ref/ref2.tex
@@ -101,7 +101,7 @@
 the end of a string, and to interpret the contents of Unicode literals.
 String literals are converted to Unicode for syntactical analysis,
 then converted back to their original encoding before interpretation
-starts.
+starts. The encoding declaration must appear on a line of its own.
 
 \subsection{Explicit line joining\label{explicit-joining}}