@InProceedings{HH03b,
author = {Ralf Hartmann and Paul Houston},
title = {Goal-Oriented A Posteriori Error Estimation for Multiple Target Functionals},
booktitle = {Hyperbolic problems: theory, numerics, applications},
pages = {579-588},
year = 2003,
editor = {Thomas Y. Hou and Eitan Tadmor},
publisher = {Springer},
}