Excel and VBA links
I have found the following web sites extremely helpful on Excel and VBA.

* John Walkenbach includes an excellent collection of links to other Excel sites.
* Stephen Bullen
* David McRitchie
* Chip Pearson

High precision calculations in Excel
* Leonardo Volpi has a highly impressive multi-precision add-in for Excel with a huge collection of mathematical and scientific functions. His approach is to deal with very big numbers as text strings so that they fit into individual cells.
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