DeVellis, R. F. (1991). Scale development: Theory and applications. Sage.
Lua i Stíl Chicago (17ú heag.)DeVellis, Robert F. Scale Development: Theory and Applications. Newbury Park, Calif.: Sage, 1991.
Lua MLA (8ú heag.)DeVellis, Robert F. Scale Development: Theory and Applications. Sage, 1991.
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