Software Safety. - Alan C. Tribble (IEEE Softw., 2002)

Proving the Shalls. - Steven P. Miller; Alan C. Tribble; Mats Per Erik Heimdahl (FME, 2003)

Proving the shalls. - Steven P. Miller; Alan C. Tribble; Michael W. Whalen; Mats Per Erik Heimdahl (Int. J. Softw. Tools Technol. Transf., 2006)