6Bauer, L., &Nation, I. S. P. Word families. International Journal of Lexicography[J], 1993,6:253 - 279.
7Cobb, T. & Horst, M. Growing academic vocabulary with a collaborative online database. In B. Morrison, D. Gardner,K. Kocbke, & M. Spratt ( Eds. ), LT Perspectives on IT & Multimedia[C]. Hong Kong: Polytechnic University Press,2001 : 189 - 226.
8Cobb, T. Analyzing late interlanguage with learner corpora:Quebec replications of three European studies[J]. Canadian Modem Language Review,2003,59 ( 3 ) : 393 - 423.
9Coxhead, A. A new academic word list [ J ]. TESOL Quarterly ,2000,34(2) :213 - 238.
10Meara, P. & Fitzpatrick, T. Lex30: An improved method of assessing productive vocabulary in an L2. System [ J ],2000, 28 (1) :19 -30.
