[tz] SGT abbreviation is missing from the IANA tz database

[Guy Harris]

On Feb 20, 2018, at 2:40 PM, Paul Eggert <eggert at cs.ucla.edu> wrote:

> On 02/19/2018 06:55 PM, Lu, Can via tz wrote:
>> SGT is very commonly used in Singapore and it’s also a standard abbreviation for Singapore time. Please refer to: https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations and https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations
> 
> Those two sources

One source, actually - both point at the same Wikipedia page...

> are not reliable for real-world use, as they're derived from old versions of the tz database itself.

...which has

	This article includes a list of references, but its sources remain unclear because it has insufficient inline citations.

at the top.  It has 7 references (plus a non-reference footnote), one of which (for Ireland) is to a law, and the rest of which point to Web sites that may or may not be authoritative - e.g., they may just be using the tzdb as their source.  Most of the time zone abbreviations have *no* reference, so, again, they may have gotten the abbreviations from the tzdb, in Yet Another case of a process similar to citeogenesis:

	https://xkcd.com/978/