Is it possible to breakdown link to a separate workbook
 

I would like to be able to display in a cell the root of the workbooks being
linked to.
And have cells below this, use the roots together with a cell reference to
retrieve data.
EG
a1: 'c:\data\[spreadsheet1]page1'
a2: 'c:\data\[spreadsheet2]page1'

a4: sum of cell b1 in spreadsheets named above

Any help would be much appreciated