For further information ...

FEDERAL GOVERNMENT LINKS:
US Department of State Travel Advisories https://travel.state.gov/content/travel/en/traveladvisories/traveladvisories.html
US Department of Homeland Security Daily Open Source Infrastructure Reports:  http://www.dhs.gov/files/programs/editorial_0542.shtm

DEPARTMENT OF DEFENSE LINKS:
Defense Security Service:  http://www.dcsa.mil

FORMS AND PUBS LINKS
DD Form 254 - DOD Contract Security Classification Specification
Standard Form 312 - Classified Information Non-Disclosure Agreement
National Industrial Security Program Operating Manual (NISPOM)

Know your reporting requirements: