Cita APA (7th ed.)

Webb, E. J. (1966). Unobtrusive measures: Nonreactive research in the social sciences. Rand McNally.

Cita Chicago (17th ed.)

Webb, Eugene J. Unobtrusive Measures: Nonreactive Research in the Social Sciences. Chicago: Rand McNally, 1966.

Cita MLA (9th ed.)

Webb, Eugene J. Unobtrusive Measures: Nonreactive Research in the Social Sciences. Rand McNally, 1966.