Physical studies of minor planets: Edited by T. Gehrels. Proceedings of the 12th Colloquium of the IAU in Tucson, Ariz., March 6–10, 1971. xxvii + 687 pp. supported and published by NASA (SP-267). For sale at U.S. Government Printing Office, Washington, DC 20402, Stock Number 3300-0428. Paper cover $3.00 (hard cover also available)