Beins, B. C. (2019). Research Methods (4th.). Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Beins, Bernard C. Research Methods. 4th. Cambridge University Press, 2019.
Lua MLA (9ú heag.)Beins, Bernard C. Research Methods. 4th. Cambridge University Press, 2019.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.