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.
Emch M, Root ED, Giebultowicz S, Ali M, Perez-Heydrich C, Yunus M.Emch M, et al.Ann Assoc Am Geogr. 2012;105(5):1004-1015. doi: 10.1080/00045608.2012.671129.Ann Assoc Am Geogr. 2012.PMID: 24163443Free PMC article.