Cheng, V.H.L., G.M. Diaz, and B. Sridhar. "Flight Safety Analysis Tool for Space Vehicle Operations in the National Airspace." in AIAA's 3rd Annual Aviation Technology, Integration, & Operations (ATIO) Forum (November 2003). Reston, Virginia: American Institute of Aeronautics and Astronautics, 2003.

Cheng, V.H.L., G.M. Diaz, and B. Sridhar. "Flight Safety Analysis Tool for Space Vehicle Operations in the National Airspace." in AIAA's 3rd Annual Aviation Technology, Integration, & Operations (ATIO) Forum (November 2003). Reston, Virginia: American Institute of Aeronautics and Astronautics, 2003.