@techreport{oai:waseda.repo.nii.ac.jp:00006720,
 author = {Shimizu, Kazumi and Fukumoto, Kentaro and Watabe, Motoki and Morimoto, Yuko},
 month = {},
 title = {Easy Issue for Me, Hard Issue for Them: Field Experiment in Large Social Survey},
 year = {2008}
}