1.

Amblee,N.andBui,T. FreewareDownloads:
A Empirical Investigation into the Impact of Expert and User Reviews on Demand for Digital Goods,
America Conference on Information Systems, Keystone, Colorado. (2007)

2.
   

Liu,Y.      
Word　of　Mouth　for　Movies:　Its　Dynamics　an　Impact　on　Box　Office　Revenue,
JournalofMarketing 70:74－89(2006).