Christensen, L. B. (2001). Experimental methodology (8th ed.). Allyn & Bacon.
Lua i Stíl Chicago (17ú heag.)Christensen, Larry B. Experimental Methodology. 8th ed. Boston: Allyn & Bacon, 2001.
Lua MLA (9ú heag.)Christensen, Larry B. Experimental Methodology. 8th ed. Allyn & Bacon, 2001.
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