1. Should we use characteristics of conversation to measure grammatical complexity in L2 writing?;Biber;TESOL Quarterly,2011
2. British Council (no date). Task 2 writing band descriptors (public version). Accessed 09/06/2014 from http://takeielts.britishcouncil.org/sites/default/files/IELTS_task_2_Writing_band_descriptors.pdf.
3. The development of abstraction in adolescence in subject English;Christie,2002
4. The ontogenesis of writing in childhood and adolescence;Christie,2010
5. School discourse: Learning to write across the years of schooling;Christie,2008