LEWIS-BECK MICHAEL S. (1993). EXPERIMENTAL DESIGN AND METHODS. SAGE PUBLICATIONS.
Lua i Stíl Chicago (17ú heag.)LEWIS-BECK MICHAEL S. EXPERIMENTAL DESIGN AND METHODS. LONDON: SAGE PUBLICATIONS, 1993.
Lua MLA (9ú heag.)LEWIS-BECK MICHAEL S. EXPERIMENTAL DESIGN AND METHODS. SAGE PUBLICATIONS, 1993.
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