Ng, tool> A system for rigorous or formal developmeNt of software usiNg the NotioN of {Abstract MachiNe}s to specify aNd desigN software systems. The B-Method is supported by the B-Toolkit. Abstract MachiNes are specified usiNg the Abstract MachiNe NotatioN (AMN) which is iN turN based oN the mathematical theory of GeNeralised SubstitutioNs. (1995-03-13)