Structured Relation Discovery using Generative Models, Limin Yao, Aria Haghighi, Sebastian Riedel and Andrew McCallum, Proceedings of the Conference on Empirical methods in natural language processing (EMNLP) 2011 [pdf] 
@inproceedings{yao11structured,
    month={July}, 
    year={2011}, 
    author={Limin Yao and Aria Haghighi and Sebastian Riedel and Andrew McCallum}, 
    bdsk-url-1={http://www.aclweb.org/anthology/D/D11/D11-1135.pdf}, 
    booktitle={Proceedings of the Conference on Empirical methods in natural language processing (EMNLP)}, 
    title={Structured Relation Discovery using Generative Models}, 
}