given for function PAT at the bottom of Table 3 in [@ISO-8731-2:1992 Annex A] and [@Davies-Clayden-88] (see Annex \[ERRATA-8731\] of the present article for details). We also corrected the handwritten implementation in C of the function imported by the aforementioned LOTOS specification (this illustrates the risks arising when formal and non-formal codes are mixed).

It is however fair to warn the reader that term rewrite systems are a low-level theoretical model that does not scale well to large problems. The REC specification is between two and six times longer than any other (formal or informal) description of the MAA, and it took considerable effort to come up with a REC specification that is readable, properly structured, and seemingly straightforward. Similar results might not be easy to reproduce on a regular basis with other case studies.

Acknowledgements {#acknowledgements .unnumbered}
----------------

We are grateful to Keith Lockstone for his advices and his web site[^3] giving useful information about the MAA, and to Sharon Wilson, librarian of the National Physical Laboratory, who provided us with valuable early NPL reports that cannot be fetched from the web.

Errata Concerning Annex A of the ISO-8731-2:1992 Standard {#ERRATA-8731}
=========================================================

After checking carefully all the test vectors 