Zy. Wei et Yt. Zhu, THE EXTENDED JORDANS LEMMA AND THE RELATION BETWEEN LAPLACE TRANSFORMAND FOURIER-TRANSFORM, Applied mathematics and mechanics, 18(6), 1997, pp. 571-574
Jordan's lemma can be used for a wider range than the original one. Th
e extended Jordan's lemma can be described as follows. Let f(z) be ana
lytic in the upper half of the z plane (Imz greater than or equal to 0
), with the exception of a finite number of isolated singularities, an
d for p>0, [GRAPHICS] then [GRAPHICS] where z=Re-i phi and CR is the o
pen semicircle in the upper half of the z plane. With the extended Jor
dan's lemma one can find that Laplace transform and Fourier transform
are a pair of integral transforms which relate to each other.