Evaluate the Klein-Gordon action

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[SOLVED] Evaluate the Klein-Gordon action

I'm interested in evaluating the Klein-Gordon action in P&S, p. 287. It goes as follows
<br /> S_0 = \frac{1}{2} \int d^4 x \! \phi \left( - \partial^2 -m^2 \right) \phi + \left(\text{surface term} \right)<br />
The surface terms drops out, that's fine. I would like to see a detailed calculation of the first part of the integral. Anyone to the rescue?

Thanks in advance!
 
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I came to my own rescue, it seems (or rather Mark Srednicki did). For reference, the evaluation is done in his "Quantum Field Theory", p. 55. A draft version may be downloaded from professor Srecnicki's homepage. I'm not allowed to post URL's quite yet, but google his name and you'll find his homepage.
 
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