On domination perfect graphs

Let $\gamma (G)$ and $\beta (G)$ denote the domination number and the covering number of a graph $G$, respectively. A connected non-trivial graph $G$ is said to be $\gamma \beta$-{perfect} if $\gamma (H)=\beta (H)$ for every non-trivial induced connected subgraph $H$ of $G$. In this note we present an elementary proof of a characterization of the $\gamma \beta$-perfect graphs.