"noyb" wrote
.. what does the ' as in ("'" do in this formula ..

The single quotes / apostrophes (there's actually a pair of them) allows
any worksheet name to be accommodated in A1

Best that I quote this advisory from a post by Harlan:

".. *ALWAYS* (and I *DO* mean **ALWAYS**) include single quotes around
worksheet names when constructing textrefs inside INDIRECT calls. The result
is far more robust since without them worksheet names that contain spaces or
exclamation points (along with a few others that require single quote
delimiters) will choke INDIRECT so that it returns #REF!. Even if the
worksheet name doesn't require single quote delimiters, no harm done adding
them. .. "
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Rgds
Max
xl 97
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