Creswell, J. W. (1994). Research design: Qualitative & quantitative approaches. Sage Publications.
Lua i Stíl Chicago (17ú heag.)Creswell, John W. Research Design: Qualitative & Quantitative Approaches. Thousand Oaks, Calif.: Sage Publications, 1994.
Lua MLA (8ú heag.)Creswell, John W. Research Design: Qualitative & Quantitative Approaches. Sage Publications, 1994.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.