Spector, P. E. (1992). Summated rating scale construction: An introduction. Sage.
Lua i Stíl Chicago (17ú heag.)Spector, Paul E. Summated Rating Scale Construction: An Introduction. Newbury Park, Calif: Sage, 1992.
Lua MLA (9ú heag.)Spector, Paul E. Summated Rating Scale Construction: An Introduction. Sage, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.