1. Extraterrestrial Cause for the Cretaceous-Tertiary Extinction
2. Impacts on the Earth by asteroids and comets: assessing the hazard
3. Spaceguard Integrated System for Potentially Hazardous Objects Survey, (SISyPHOS), ESA contract 13265/98/D/IM (1999)
4. Study on the distribution of NEO's. ESA contract 14018/00/F/TB, (2001) http://www.obs-nice.fr/michel/Debiased_NEO.pdf
5. NEO hazard mitigation publication survey. ESA contract RFQ/14472/00/D-HK (2001)