How to get the curly caligraphic font for sigma algebras?

The title pretty much says it all.

Note that I am aware of the caligraphic font (cal, mathcal) which is actually what wikipedia uses too but books on the measure theory usually contain a much fancier font with many loops and I'd like to use it too if possible.

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\usepackage{mathrsfs}
...
$\mathscr{A}$

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Thank you. I'll just add for general convenience that in plain one can use "\input scrload" and macro \scr. –  Marek Jun 4 '11 at 11:08