Function GetXRefs() As Collection
Dim ThisBlock As AcadBlock
Dim ThisObject As AcadEntity
Dim AnXRef As AcadExternalReference
Dim Result As New Collection
Dim i As Integer
For Each ThisBlock In ThisDrawing.Blocks
 For Each ThisObject In ThisBlock
  If TypeOf ThisObject Is AcadExternalReference Then
   Set AnXRef = ThisObject
   Result.Add AnXRef, CStr(i)
   i = i + 1
  End If
 Next ThisObject
Next ThisBlock
Set GetXRefs = Result
Set Result = Nothing
End Function