  We give necessary and sufficient condition for existence and uniqueness of
$\mathbb{L}^{p}$-solutions of reflected BSDEs with continuous barrier,
generator monotone with respect to $y$ and Lipschitz continuous with respect to
$z$, and with data in $\mathbb{L}^{p}$, $p\ge 1$. We also prove that the
solutions may be approximated by the penalization method.
