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.
Cao D, Bridges F, Kowach GR, Ramirez AP.Cao D, et al. Among authors: kowach gr.Phys Rev Lett. 2002 Nov 18;89(21):215902. doi: 10.1103/PhysRevLett.89.215902. Epub 2002 Nov 4.Phys Rev Lett. 2002.PMID: 12443433