题目：Innovation and cooperation under vertical product differentiation
链接：http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V8P-3Y5FD8R-V&_user=10&_coverDate=03%2F31%2F1995&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1419259390&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=25e0e1c7ac0a49fbb8de3e6df322e220

题目：Cooperative R&D and vertical product differentiation
链接：http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V8P-45F8Y7N-1V&_user=10&_coverDate=12%2F31%2F1992&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1419260490&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8d070de5f1ebaa6c1df77512d584cdeb