This Week in Science This Week in Science Science 19 May 1989:Vol. 244, Issue 4906, pp. 751DOI: 10.1126/science.244.4906.751 Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears above.
Science Vol 244, Issue 490619 May 1989 Table of Contents Print Table of Contents Back Matter (PDF) Ed Board (PDF) Front Matter (PDF)