TS_TG1-039-2 is a second number in the same series as the other TS_TG1 document listed on this site, and the two share their first group of digits while differing in the second, which in a specification of this structure normally indicates that they address different subjects or different classes of component within one manufacturer's scheme. A supplier encountering the series should establish its full extent, obtain the parts named in the engineering specification and confirm their editions, since the parts are revised independently and a requirement is only as current as the edition being worked to. Because the series is internal to its issuer, the document cannot be verified from public sources, and that is why the note on this page asks for the issuer to be confirmed. A supplier who receives only one number of the series and completes the work against it may still be asked for evidence against a clause that appears in another part, and that evidence then has to be produced after the fact.