diff --git a/Set_movable_separability_2/doc/Set_movable_separability_2/Set_movable_separability_2.txt b/Set_movable_separability_2/doc/Set_movable_separability_2/Set_movable_separability_2.txt
index ff6040e00f6..9135679be23 100644
--- a/Set_movable_separability_2/doc/Set_movable_separability_2/Set_movable_separability_2.txt
+++ b/Set_movable_separability_2/doc/Set_movable_separability_2/Set_movable_separability_2.txt
@@ -9,9 +9,6 @@ namespace CGAL {
 
 \section sms_sec_intro Introduction
 
-Chapter \ref Chapter_2D_Regularized_Boolean_Set-Operations
-"2D Regularized Boolean Set-Operations"
-
 <em>Movable Separability of Sets</em> \cgalCite{t-mss-85} is a class
 of problems that deal with moving sets of objects, such as polygons in
 the plane; the challange is to avoid collisions between the objects