Lee, R. M. (2000). Unobtrusive methods in social research. Open University Press.
Lua i Stíl Chicago (17ú heag.)Lee, Raymond M. Unobtrusive Methods in Social Research. Buckingham [England]: Open University Press, 2000.
Lua MLA (9ú heag.)Lee, Raymond M. Unobtrusive Methods in Social Research. Open University Press, 2000.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.