Primitive of Reciprocal of x cubed plus a cubed squared

Theorem

 * $\displaystyle \int \frac {\mathrm d x} {\left({x^3 + a^3}\right)^2} = \frac x {3 a^3 \left({x^3 + a^3}\right)} + \frac 1 {9 a^5} \ln \left({\frac {\left({x + a}\right)^2} {x^2 - a x + a^2} }\right) + \frac 2 {3 a^5 \sqrt 3} \arctan \frac {2 x - a} {a \sqrt 3}$