Need help with this Lebesgue Integration problem. I have no clue as to how to do this. Could Fubini-Tonelli be required? Is there some reference I could read to understand how to attempt such problems?
Let $f$ be a measurable function and $E$ be a measurable subset of $\mathbb{R}^n$. 
Show that: 
$$\int_{E} |f|^p \ dm \ = \ \int_{0}^{\infty} pt^{p-1}m\{\ \textbf{x}\in E : |f(\textbf{x})|\gt t \} dt$$

Hint: write the right-hand side as
$$ \int_0^{\infty}pt^{p-1}\int_E1_{|f(x)|>t}\; dmdt$$
and use Tonelli's theorem to interchange the integrals.
