Maximum principle for parabolic systems

We show, under very general assumptions on the datum $u$, that Cauchy–Dirichlet problem
$$ \begin{cases} -\sum\limits_{ij=1}^nD_i(A^0_{ij}D_j v)+\frac{\partial v}{\partial t}=0\quad\text{in}\quad Q,\\ v=u\quad\text{on the parabolic boundary $\Gamma_Q$ of $Q$} \end{cases} $$
admits a unique bounded solution.