Kaizhu Huang Zenglin Xu Irwin King Michael R. Lyu Semi-supervised Learning from General Unlabeled Data. 273-282 2008 ICDM http://dx.doi.org/10.1109/ICDM.2008.61 conf/icdm/2008 db/conf/icdm/icdm2008.html#HuangXKL08