Unsupervised feature learning for audio classification using convolutional deep belief networks. - Honglak Lee; Peter T. Pham; Yan Largman; Andrew Y. Ng (NIPS, 2009)

Learning Word Vectors for Sentiment Analysis. - Andrew L. Maas; Raymond E. Daly; Peter T. Pham; Dan Huang; Andrew Y. Ng; Christopher Potts (ACL, 2011)