Barrett, J. (2007). Test your numerical aptitude: How to assess your numeracy skills and plan your career. Kogan Page.
Chicago-viite (17. p.)Barrett, Jim. Test Your Numerical Aptitude: How to Assess Your Numeracy Skills and Plan Your Career. London: Kogan Page, 2007.
MLA-viite (9. p.)Barrett, Jim. Test Your Numerical Aptitude: How to Assess Your Numeracy Skills and Plan Your Career. Kogan Page, 2007.
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