Cell Reference Style

A workbook saved with reference style A1 (§, shall have the @refMode attribute of the <calcPr> element (§3.2.2) in the Workbook part's XML omitted or set to A1. A workbook saved with reference style R1C1 (§ shall have that @refMode attribute set to R1C1.
example: : With R1C1 mode set, here is how the XML might look:
<workbook …>
  <calcPr calcId="122211" fullCalcOnLoad="1" refMode="R1C1"/></workbook>
Regardless of the value of the @refMode attribute, cell references shall be stored in XML in the A1 form.
Note: : This attribute's value tells an implementation which reference style to use at runtime.