5LEV B, SOUGIANNIS T. The capitalization, amortization, and value-relevance of R&D[J]. Journal of Accounting and Economics, 1996,21 : 107-138.
6ABOODY D. The value relevance of intangibles: the case of software capitalization[J].Journal of Accounting Research( supplement), 1998 : 235-247.
7LEV B, ZAROWIN P. The boundaries of financial reporting and how to extend tbem[J]. Journal of Accounting Research, 1999,37(2) : 353-385.
8CHAN L K C, LAKONISHOK J,SOUGIANNIS T. The stock market valuation of research and development expenditures[J]. Journal of finance, 2001 (12) : 2431-2456.
