Link to the original paper. There seems to be a growing body of published work on this subject. http://jop.sagepub.com/content/early/2014/03/17/026988111452736

Link to the original paper. There seems to be a growing body of published work on this subject. http://jop.sagepub.com/content/early/2014/03/17/0269881114527361.full.pdf+html http://jop.sagepub.com/content/early/2014/03/17/026988111452...