Hi Narska,
It is a special autotext combination:
<MARKERDRAWINGNUMBER_R><guid><NULLGUID><NULLGUID>
or
<MARKERSHEETNUMBER_R><guid><NULLGUID><NULLGUID>
AC_DrawingGUID parameter will contain the <guid><NULLGUID><NULLGUID> string that refers to the layout/drawing.
See the "Marker Link Parameters" macro for an example.
Péter Baksa
Software Engineer, Library as a Platform
Graphisoft SE, Budapest