APA (7th ed.) Zitazioa
Spector, P. E. (1981). Research designs. Sage Publications.
Chicago Style (17th ed.) Zitazioa
Spector, Paul E. Research Designs. Beverly Hills: Sage Publications, 1981.
MLA (9th ed.) Zitazioa
Spector, Paul E. Research Designs. Sage Publications, 1981.
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