Jesper Norgaard Welen <jnorgard@prodigy.net.mx> writes:
http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/capitulo5.h...
Yes, that's section 5 of the history of Mexican local time that <http://www.twinsun.com/tz/tz-link.htm> points to.
If everything is taken literally, there are at least a need to introduce new timezones for the states Campeche, Tamaulipas, Tabasco+CHS, Baja California Sur, Durango, Veracruz+Oaxaca, and Coahuila.
Do these states have time zone histories that differ since 1970? If so, we would need new entries for them. (I don't read Spanish well, alas).
Before I go too far with deciphering this, I would like to hear the general opinion about if this is an authoritative source or not - after all the Congress only recently got authority over timezone issues in Mexico (formally), and this list might have some goofed up details from extracting from old documents by "new" people.
That could be, yes. But I'm not really qualified to judge this, unfortunately.