APA (7th ed.) Zitazioa
Webb, E. J., Campbell, D. T., Schwartz, R. D., & Sechrest, L. (1966). Unobtrusive measures: Nonreactive research in the social sciences. Rand McNally.
Chicago Style (17th ed.) Zitazioa
Webb, Eugene J., Donald T. Campbell, Richard D. Schwartz, eta Lee Sechrest. Unobtrusive Measures: Nonreactive Research in the Social Sciences. Chicago: Rand McNally, 1966.
MLA (9th ed.) Zitazioa
Webb, Eugene J., et al. Unobtrusive Measures: Nonreactive Research in the Social Sciences. Rand McNally, 1966.
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