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.
Eklund A, Hällgren R, Blaschke E, Engström-Laurent A, Persson U, Svane B.Eklund A, et al.Eur J Respir Dis. 1987 Jul;71(1):30-6.Eur J Respir Dis. 1987.PMID: 2820777