diff --git a/songbook.tex b/songbook.tex
index 5e62f3a..d72e204 100644
--- a/songbook.tex
+++ b/songbook.tex
@@ -5,6 +5,7 @@
 \usepackage[utf8]{inputenc}
 \usepackage[T1]{fontenc}
 
+% les classes clefs pour la musique
 \usepackage[chordbk,compactsong]{songbook}
 \usepackage{musixtex}