Please cite as:

@article{scheines1998tetrad,
title={The TETRAD project: Constraint based aids to causal model specification},
author={Scheines, Richard and Spirtes, Peter and Glymour, Clark and Meek, Christopher and Richardson, Thomas},
journal={Multivariate Behavioral Research},
volume={33},
number={1},
pages={65--117},
year={1998},
publisher={Taylor \& Francis}
}