 Additionally , we obtain two alternative error estimates , which are efficient to guide refinements. Several numerical examples illustrate the framework's performance on diffusion-advection-reaction problems.
<clarity>  Additionally , we obtain two alternative error estimates , which are efficient to guide refinements. Several numerical examples illustrate the framework's performance on diffusion-advection-reaction problems.
 Additionally , we obtain two efficient error estimates to guide goal-oriented adaptivity. We illustrate the performance of this goal-oriented adaptive strategy on advection-diffusion-reaction problems.