A remark on existence and optimal summability of solutions of elliptic problems involving Hardy potential

\begin{abstract} We study the effect of a zero order term on existence and optimal summability of solutions to the elliptic problem $$ -\text{div}( M(x)\nabla u)- a\dfrac{u}{|x|^2}=f \hbox{ in } \Omega\,, \qquad u=0 \hbox{ on } \partial \Omega\,, $$ with respect to the summability of $f$ and the value of the parameter $a$. Here $\Omega$ is a bounded domain in $\mathbb{R}^N$ containing the origin. \end{abstract}