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.
Semerdjieva I, Sidjimova B, Yankova-Tsvetkova E, Kostova M, Zheljazkov VD.Semerdjieva I, et al. Among authors: sidjimova b.Heliyon. 2019 Dec 13;5(12):e03021. doi: 10.1016/j.heliyon.2019.e03021. eCollection 2019 Dec.Heliyon. 2019.PMID: 32373724Free PMC article.