Try this link for revised A-21, etc.  It was very helpful.

>SUMMARY: On May 10, 2004, the Office of Management and Budget (OMB)
>published a notice in the Federal Register announcing the final
>revisions to the cost principles in Circulars A-21, A-87 and A-122.
>These final cost principles are effective June 9, 2004. (See pp.
>25970-25995 of the Federal Register or
>http://www.thefdp.org/FR_0410350.pdf
>
>--------------------------------------------------------

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