Edmondson, E. (1999). Twelve Lectures on Second Language Acquisition. Germany: Gunter Narr Verlag Tubingen.
Bower, J., & Kawaguchi, S. (2011). Negotiation of Meaning and Corrective Feedback in Japanese/English e-Tandem. Language Learning and Technology. (15)1, 41-71.
Ellis, R. (1985). Understanding Second Language Acquisition. Oxford: Blackwell Publishers Ltd.
Ellis, R. (1990). Instructed Second Language Acquisition: Learning in the Classroom. Oxford: Blackwell Publishers Ltd.
Farangis, Saeedi. (2013). The Effect of Negotiation on Second Language Acquisition. Education Journal. (2)6, 236-241. DOI: 10.11648/j.edu.20130206.15 
Fang, X. (2010). The role of input and interaction in second language acquisition. Cross Cultural Communication. 6(1), 11-17.
Foster, P., & Ohta, A. S. (2005). Negotiation for Meaning and Peer Assistance in Second Language Clasrooms. Applied Linguistics. 3 (26), 402-430. DOI: 10.1093/applin/ami014
Gass, S., & Selinker, L.  (2008). Second Language Acqusition: An Introductory Course (3rd Edition). New York, NY: Routledge. 
Larsen-Freeman, D., & Long, M. H. (1991). An Introduction to Second Language Acquisition Research. New York, NY: Longman.
Lightbown, P.P., & Spada, N. (2000). How Languages are Learned (2nd ed). New York, NY: Oxford University Press.
Long, M. (1985). Native speaker/ non-native speaker conversation and the negotiation of comprehensible input. Applied Linguistics. 4, 126-141. 
Mackey, A. (1999). Input, Interaction and Second Language development: An Empirical Study Question Formation in ESL. Studies in Second Language Acqusition. 21, 557-587.
Smith, M.S. (1994). Second Language Learning: Theoretical Foundations. New York: Longman.
Towell, H., & Hawkins, R. (1994). Approaches to Second Language Acquisition. UK: Multilingual Matters Ltd.
Trawinski, M. (2005). An Outline of Second Language Acquisition Theories. Krakow, Poland: Wydawnictwo Naukowe Akademii Pedagogicznej.
Zhang, S. (2009). The role of input, interaction and output in the development of Oral fluency. English Language Teaching. 2(4), 91-100. Retrieved from www.ccsenet.org/journal.html