\[f(t)=\frac{1}{2\pi\mathrm{i}}\lim_{T\to\infty}\int^{\sigma+\mathrm{i}T}_{%
\sigma-\mathrm{i}T}{\mathrm{e}}^{ts}\mathscr{L}\mskip-3.0muf\mskip 3.0mu\left(%
s\right)\,\mathrm{d}s,\]