3Crookes, G. 1989. "Planning and interlanguage variation". Studies in Second Language Acquisition 11/3: 367-383.
4Crookes, G. 1990. "The utterance, and the other basic units for second language discourse analysis~. Applied Linguistics 11 : 183-199.
5Doughty, C. 1991. "Second language instruction does make a difference, evidence from an empirical study of SL relativization". Studies in Second Language Acquisition 13/4 : 431 - 470.
6Ellis, R. 1987. "Interlanguage variability in narrative discourse: style shifting in the use of the past tense". Studies in Second Language Acquisition 9 ; 12-20.
7Foster, P. & P. Skehan. 1996. "The influence of planning and task type on second language performanee ". Studies in Second language Acquisition 18:299-323.
8Long, M. 1991. "Focus on form: a design feature in language teaching". In K. de Bot, R.B. Ginsberg & C. Kramsch ( eds. ). Foreign Language Research in Cross-cultural Perspective. Amsterdam: John Benjamins.
9Perron, J. 1977. "Written syntactic complexity and the modes of discourse'. Paper presented at the annual meeting of the American Educational Research Association, New York.
10Schachter, J. 1974. "An error in error analysis". Language Learning 24 : 205- 214.