Nonreactive measures in the social sciences / Eugene T. [i.e. J.] Webb ... [et al.]. - 2nd ed. - Boston : Houghton Mifflin, c1981. - x, 394 p. ; 22 cm. Previous ed.: Unobtrusive measures. 1966. Includes index. Bibliography: p. 331-378. ISBN: 0395307678 LCCN: 80050984 Subjects--Topical Terms: Social sciences--Research. LC Class. No.: H62 / .N675 1981 Dewey Class. No.: 302.72 / NON 1981