Letters Importing biological materials See allHide authors and affiliations Science 13 Dec 1991:Vol. 254, Issue 5038, pp. 1566DOI: 10.1126/science.1749928 S PestkaFind this author on Google Scholar Find this author on PubMed Search for this author on this site Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 254, Issue 503813 December 1991 Table of Contents Print Table of Contents Back Matter (PDF) Ed Board (PDF) Front Matter (PDF)
