1. ACTFL 2012 ACTFL Proficiency Guidelines https://www.actfl.org/publications/guidelines-and-manuals/actfl-proficiency-guidelines-2012
2. ACTFL 2015 NCSSFL-ACTFL Can-Do Statements http://www.actfl.org/global_statements
3. Supply-chain trade: A portrait of global patterns and several testable hypotheses;Baldwin;The World Economy,2015
4. Foreign language proficiency levels attained by language majors near graduation from college;Carroll;Foreign Language Annals,1967
5. Cohen , P. 2016 A rising call to promote STEM education and cut liberal arts funding http://www.nytimes.com/2016/02/22/business/a-rising-call-to-promote-stem-education-and-cut-liberal-arts-funding.html?_r=0