I am dealing with a physics problem and I have to perform the following integral,
\begin{equation} \int \dfrac{d^3k}{(2\pi)^3}\dfrac{e^{ikr}}{k^4} \end{equation}
I know that if the exponent in the denominator was a 2, the result is the Coulomb potential $1/(4\pi r)$ (see https://en.wikipedia.org/wiki/Common_integrals_in_quantum_field_theory), but I didn't found anything about a 4 in the denominator. Does anybody know the result of this integral?