All links of Planetary Defense

ImpactImpact
Meteor DefenseMeteor Defense
BBC News: Government Prepares for Space ImpactBBC News: Government Prepares for Space Impact
U.S. Summons Experts to Draft Asteroid Defense PlanU.S. Summons Experts to Draft Asteroid Defense Plan
China Daily: Dangerous Space Rocks Under WatchChina Daily: Dangerous Space Rocks Under Watch
Impact ParametersImpact Parameters
The SpaceGuard CentreThe SpaceGuard Centre

Planetary Defense related site: