1. American Association for Public Opinion Research. (2016). Standard definitions: Final dispositions of case codes and outcome rates for surveys. 9th edition. AAPOR. https://www.aapor.org/AAPOR_Main/media/publications/Standard Definitions20169theditionfinal.pdf
2. American Educational Research Association. (2011). Code of ethics. American Educational Research Association. Approved by the AERA Council, February 2011, www.aera.net/Portals/38/docs/About_AERA/CodeOfEthics(1).pdf. Accessed 9 Sep 2018.
3. American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., text rev). Author.
4. American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Author.
5. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Author.