@ARTICLE {1055,
author={J. J. Júdice and A. Pinto da Costa and J. Martins and I. Figueiredo},
doi={10.1016/j.cma.2003.09.013},
journal={Computer Methods in Applied Mechanics and Engineering},
title={The directional instability problem in systems with frictional contacts},
year={2004},
month={January},
volume={193},
number={1},
pages={357-384},
ISSN={0045-7825}
}