Authors (if indicated). Organization responsible for the site. Title of page or document. Available at: URL. Accessed Month day, year.
Examples
Food and Drug Administration. MedWatch. Available at: http://www.fda.gov/medwatch/index.html. Accessed June 13, 2007.American Diabetes Association. Gestational diabetes. Available at: http://www.diabetes.org/gestational-diabetes.jsp. Accessed June 13, 2007.