diff --git a/Segment_Delaunay_graph_Linf_2/include/CGAL/Polychain_2.h b/Segment_Delaunay_graph_Linf_2/include/CGAL/Polychain_2.h
index 6ec4a820fac..8927d82d99b 100644
--- a/Segment_Delaunay_graph_Linf_2/include/CGAL/Polychain_2.h
+++ b/Segment_Delaunay_graph_Linf_2/include/CGAL/Polychain_2.h
@@ -25,6 +25,7 @@
 #include <CGAL/basic.h>
 #include <CGAL/Polygon_2.h>
 #include <CGAL/intersections.h>
+#include <CGAL/Segment_Delaunay_graph_Linf_2/basic.h>
 
 
 // Polychainsegment_2
diff --git a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
index 001df0d632c..413622bd2fb 100644
--- a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
+++ b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
@@ -30,7 +30,7 @@
 #include <CGAL/enum.h>
 #include <CGAL/Orientation_Linf_2.h>
 #include <CGAL/tuple.h>
-
+#include <CGAL/Segment_Delaunay_graph_Linf_2/basic.h>
 namespace CGAL {
 
     template<class K>
diff --git a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_oriented_square_2.h b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_oriented_square_2.h
index de7049ea8f1..35b766c465c 100644
--- a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_oriented_square_2.h
+++ b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_oriented_square_2.h
@@ -26,6 +26,7 @@
 #include <CGAL/Orientation_Linf_2.h>
 #include <CGAL/Side_of_bounded_square_2.h>
 #include <CGAL/enum.h>
+#include <CGAL/Segment_Delaunay_graph_Linf_2/basic.h>
 
 namespace CGAL {