An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Park IK, Qian D, Kiel M, Becker MW, Pihalja M, Weissman IL, Morrison SJ, Clarke MF.Park IK, et al. Among authors: morrison sj.Nature. 2003 May 15;423(6937):302-5. doi: 10.1038/nature01587. Epub 2003 Apr 20.Nature. 2003.PMID: 12714971Free article.