http://aune.lpl.univ-aix.fr/~hirst/articles/1998%20Hirst
http://www.youtube.com/watch?v=UtmRZDvB7NA
http://ci.nii.ac.jp/naid/110008762766
http://ci.nii.ac.jp/naid/110008155346
http://ci.nii.ac.jp/naid/110008512122 On politeness, but might have a good hint for an experiment with british english speakers