diff --git a/Doc/lib/libre.tex b/Doc/lib/libre.tex
index e31ccd01076..bf4df633818 100644
--- a/Doc/lib/libre.tex
+++ b/Doc/lib/libre.tex
@@ -867,7 +867,7 @@ offers some more-or-less equivalent mappings between
   \lineii{\code{\%d}}
          {\regexp{[-+]?\e d+}}
   \lineii{\code{\%e}, \code{\%E}, \code{\%f}, \code{\%g}}
-         {\regexp{[-+]?(\e d+(\e.\e d*)?|\e d*\e.\e d+)([eE]\e d+)?}}
+         {\regexp{[-+]?(\e d+(\e.\e d*)?|\e d*\e.\e d+)([eE][-+]?\e d+)?}}
   \lineii{\code{\%i}}
          {\regexp{[-+]?(0[xX][\e dA-Fa-f]+|0[0-7]*|\e d+)}}
   \lineii{\code{\%o}}