http://en.wikipedia.org/wiki/Methods_of_contour_integration
http://www.physicsforums.com/showthread.php?t=496854
http://math.stackexchange.com/questions/135917/calculating-a-real-integral-using-complex-integration
http://www.math.odu.edu/~jhh/ch75.PDF
http://www.math.upenn.edu/~rimmer/math241/ch19sc6skeleton.pdf
http://www.mth.kcl.ac.uk/courses/cm211/19.pdf
http://www.math.umn.edu/~olver/am_/c.pdf
http://hitoshi.berkeley.edu/221a/contour.pdf
http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Mathematics/2009_August_3
http://www.absoluteastronomy.com/topics/Fresnel_integral
http://www.dsprelated.com/dspbooks/sasp/Gaussian_Integral_Complex_Offset.html
https://www.classle.net/book/application-residue-theorem