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.
Niklas KJ, Enquist BJ.Niklas KJ, et al.Proc Natl Acad Sci U S A. 2001 Feb 27;98(5):2922-7. doi: 10.1073/pnas.041590298. Epub 2001 Feb 6.Proc Natl Acad Sci U S A. 2001.PMID: 11226342Free PMC article.
Niklas KJ, Cobb ED, Niinemets U, Reich PB, Sellin A, Shipley B, Wright IJ.Niklas KJ, et al.Proc Natl Acad Sci U S A. 2007 May 22;104(21):8891-6. doi: 10.1073/pnas.0701135104. Epub 2007 May 14.Proc Natl Acad Sci U S A. 2007.PMID: 17502616Free PMC article.