diff --git a/Arrangement_on_surface_2/doc/Arrangement_on_surface_2/Arrangement_on_surface_2.txt b/Arrangement_on_surface_2/doc/Arrangement_on_surface_2/Arrangement_on_surface_2.txt
index ba6f1adb152..64d3604362f 100644
--- a/Arrangement_on_surface_2/doc/Arrangement_on_surface_2/Arrangement_on_surface_2.txt
+++ b/Arrangement_on_surface_2/doc/Arrangement_on_surface_2/Arrangement_on_surface_2.txt
@@ -1438,14 +1438,15 @@ vary according to the user choice.} for answering queries:
   points or choosing points on a grid, are also available; see the
   Reference Manual for more details.
 
-  The landmark strategy requires that the type of the attached
-  arrangement be an instance of the `Arrangement_2<Traits,Dcel>` class
-  template, where the `Traits` parameter is substituted by a
-  geometry-traits class that models the `ArrangementLandmarkTraits_2`
-  concept, which refines the basic `ArrangementBasicTraits_2` concept;
-  see Section \ref aos_sssec-tr_landmarks_concept for details. Most
-  traits classes included in the \ref PkgArrangementOnSurface2 package
-  are models of this refined concept.
+  The arrangement attached to the landmark strategy must be either (i)
+  an instance of the `Arrangement_2<Geom,Dcel>` class template, where
+  the `Traits` parameter is substituted by a geometry-traits class
+  that models the `ArrangementLandmarkTraits_2` concept, or (ii) an
+  instance of the `Arrangement_on_surface_2<GeomTraits,TopolTraits>`
+  class template, where the `GeomTraits` is similarly substituted;
+  see Section \ref aos_sssec-tr_landmarks_concept for details about
+  this concept. Most traits classes included in the \ref
+  PkgArrangementOnSurface2 package are models of this refined concept.
 
 <LI>`Arr_trapezoid_ric_point_location<Arrangement>` implements an
   improved variant of Mulmuley's point-location algorithm