Advertisements AAAS Travelers . . See allHide authors and affiliations Science 12 May 1978:Vol. 200, Issue 4342, pp. 617DOI: 10.1126/science.200.4342.617 Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 200, Issue 434212 May 1978 Table of Contents Print Table of Contents Ed Board (PDF) Front Matter (PDF)
