Extraterrestrials--where are they?
By: edited by Ben Zuckerman and Michael H. Hart.
Contributors: Hart, Michael H.; Zuckerman, Ben, 1943-
Edition: 2nd ed.
Place of publication: Cambridge ; New York
Number of pages: 239
Subjects: Life -- Origin -- Congresses.; Life on other planets -- Congresses.
Notes: Hart's name appears first on the earlier edition. "The purpose of a second edition ... is to enlarge upon and update issues that were debated in 1978 at a two-day symposium of the same name"--P. ix. Includes bibliographical references and indexes.

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