On p104 of Srednicki's QFT, he does an integral in closed form, equations 14.43 and 14.44. I just ran the calculations for this in Mathematica, and I get his answer exactly except for my constants [tex] c_1=4-\pi\sqrt{3} [/tex] and [tex] c_2=4-2\pi\sqrt{3} [/tex].

The mathematica code I used to generate this was:

Then collecting the terms in k^2 and m^2, you find the constants I posted above, rather than the very similar but different Srednicki ones.

It's not listed on his errata page if this is an error, perhaps I am missing something? just seems very close, to not be correct.