(SWEREF-235)
John C. Kelly, Joseph S. Sherif, Jonathan Hops, NASA. Goddard Space Flight Center, Proceedings of the 15th Annual Software Engineering Workshop; 35 p(SWEREF-277)
NASA-STD-8739.9, NASA Office of Safety and Mission Assurance, 2013. Change Date: 2016-10-07, Change Number: 1(SWEREF-320)
Shull., F., Feldmann, R., Seaman, C., Regardie, M., and Godfrey, S.,Innovations in Systems and Software Engineering - a NASA Journal, 2010. Available at: http://dx.doi.org/10.1007/s11334-010-0132-1.