1. 1) Noor, A. K. and Venneri, S. L., eds.: Future Aeronautical and Space Systems, AIAA, Inc., Virginia, 1997, pp. 315-327.
2. 2) Weingartner, S.: SÄNGER - The Reference Concept of the German Hypersonics Technology Program, AIAA Paper 93-5161, 1993.
3. 3) INTERNET ARCHIVE, http://web.archive.org/web/20051031100115/http://www.nasda.go.jp/press/2000/02/nasa_00020_j.html
4. 4) NASA, ftp://ftp.hq.nasa.gov/pub/pao/pressrel/2001/01-031.txt
5. 5) Decker, J. P.: Aerodynamic Interference Effects Caused by Parallel-Stage Simple Aerodynamic Configurations at Mach Number of 3 and 6, NASA TN D-5379, 1969.