t/013.xml

   1 <workbook>
   2   <worksheet name="backref">
   3     <cell ref="foo" text="1" />
   4     <cell ref="foo" text="2" />
   5     <cell ref="foo" text="3" />
   6     <cell>=SUM(<range ref="foo"/>)</cell>
   7   </worksheet>
   8 </workbook>