Products & Materials New Products See allHide authors and affiliations Science 21 Apr 1961:Vol. 133, Issue 3460, pp. 1295-1300DOI: 10.1126/science.133.3460.1295 Joshua SternFind 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 133, Issue 346021 April 1961 Table of Contents Print Table of Contents Back Matter (PDF) Ed Board (PDF) Front Matter (PDF)
