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.
Kowalik TF, Wing B, Haskill JS, Azizkhan JC, Baldwin AS Jr, Huang ES.Kowalik TF, et al.Proc Natl Acad Sci U S A. 1993 Feb 1;90(3):1107-11. doi: 10.1073/pnas.90.3.1107.Proc Natl Acad Sci U S A. 1993.PMID: 8381532Free PMC article.