@article{wang_zheng_dai_2014, 
  title={Local Empirical Likelihood Diagnosis of  Varying Coefficient Density-Ratio Models Based on Case-Control Data}, 
  volume={04}, 
  DOI={10.4236/ojs.2014.49070}, 
  number={09}, 
  publisher={Scientific Research Publishing, Inc,}, 
  author={Wang and Zheng and Dai}, 
  year={2014}
  }