1Jiandong Ju. Oligopelistic Competition, Tech- nology Innovation and Multiproduct Firms [ J ]. Review of International Economics, 2003, 11 (2) :346 -359.
2Dixit A. , Stiglitz J. Monopolistic Competition and Optimum Product Diversity [ J ]. American Economic Review, 1977,67 (3) :297 - 308.
3Bernard, Andrew B. , Stephen J. Redding and Peter K. Schott. Multiproduct Firms and Prod- uct Switching [ J ]. American Economic Review, 2010,100( 1 ) :70 -97.
4Yu, Zhihao. Economies of Scope and Patterns of Global Outsourcing [ R ]. GEP Research Pa- pers, University of Nottingham, 2005.
5Melitz Marc J. The Impact of Trade on Intra - Industry Reallocations and Aggregate Industry Productivity[ J ]. Econometrica, 2003,71 ( 6 ) : 1695 -1725.
6openhayn, Hugo A. Entry, Exit, and Firm Dy- namics in Long Run Equilibrium [ J ]. Econo- metrica,1992, 60(5) :1127 - 1150.
7Wilbur G. Lewellen. A Pure Financial Rationa- le for the Conglomerate Merger [ J ]. Joumal of Finance, 1971,26: 521 -537.
