1. Rod Ellis .1994. The Study of Second Language Acquisition . Oxford University Press , Oxford, UK . Rod Ellis.1994. The Study of Second Language Acquisition. Oxford University Press, Oxford, UK.
2. Linguistic Distance: A Quantitative Measure of the Distance between English and Other Languages;Chiswick Barry R.;J. Multiling. Multicul.,2004
3. Language distance and tree reconstruction;Petroni Filippo;J. Stat. Mech.-Theory E.,2008
4. Matthew S. Dryer and Martin Haspelmath (eds.) . 2013 . The World Atlas of Language Structures Online . Leipzig : Max Planck Institute for Evolutionary Anthropology . http://wals.info Matthew S. Dryer and Martin Haspelmath (eds.). 2013. The World Atlas of Language Structures Online. Leipzig: Max Planck Institute for Evolutionary Anthropology. http://wals.info
5. Does Ease of Communication Increase Trade? Commonality of Language and Bilateral Trade;Hutchinson William K.;Scot. J. Polit. Econ.,2003