Although an INDIRECT function could be used to generate the required reference, that function won't work with a reference to a closed workbook. The best solution for you would probably be to use Find/Replace to update the references each year. Alternatively, you might consider having all years in the same workbook. Although you could have each year in a separate worksheet on that workbook, the best long-term approach for data aggregation and analysis is to have all the data on a single worksheet. Formulae can be used to generate queries for any nominated period from a multi-year worksheet.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]