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.
el-Bassel N, Schilling RF.el-Bassel N, et al.Public Health Rep. 1992 Sep-Oct;107(5):500-4.Public Health Rep. 1992.PMID: 1410230Free PMC article.Clinical Trial.
Schilling RF, el-Bassel N, Schinke SP, Gordon K, Nichols S.Schilling RF, et al.Public Health Rep. 1991 May-Jun;106(3):297-304.Public Health Rep. 1991.PMID: 1905051Free PMC article.Clinical Trial.