4Aktas, R. N. & Cortes, V. Shell nouns as cohesive devices in pub- lished and ESL student writing [ J ]. Journal of English for Academic Purposes ,2008 (7) : 3 -14.
5Biber, D. , Johansson, S. , Leech, G. , Conrad, S. , & Finegan, E. Longman Grammar of Spoken and Written English [ M ]. Harlow : Pear- son Education, 1999.
6Charles, M. 'This mystery... ' : A corpus-based study of the use of nouns to construction stance in theses from two contrasting disciplines [J]. Journal of English for Academic Purposes, 2003(2) : 313-326.
7Connor, U. A study of cohesion and coherence in English as a second language student' s writing [ J ]. Papers in Linguistics, 1984 ( 17 ) : 301- 316.
8Flowerdew, J. Signalling nouns in discourse [ J]. English for Specific Purposes, 2003a(22) : 329-346.
9Flowerdew, J. Register-specificiy of signalling nouns in discourse[ A]. In C. Meyer & P. Leistyna (eds.). Corpus Analysis: Language Struc- ture and Language Use [ C ]. Amsterdam: Rodopi Publishers, 2003b: 35--46.
10Flowerdew, J. Use of signalling nouns in a learner corpus[J]. Interna- tional Journal of Corpus Linguistics ,2006,11 (3) : 345-362.