@techreport{ganchev:penn:2009,
    title     = {Posterior Regularization for Structured Latent Variable Models},
    author    = {Kuzman Ganchev and Joao Graca and Jennifer Gillenwater and Ben Taskar},
    institution = {University of Pennsylvania Department of Computer and Information Science},
    number = {MS-CIS-09-16},
    year = {2009}
}

@article{blei:2003,
 author={David M. Blei and Andrew Y. Ng and Michael I. Jordan and John Lafferty},
 title={Latent {Dirichlet} Allocation},
 year=2003,
 journal={Journal of Machine Learning Research},
 volume=3,
 pages={993--1022}
}