Mexico: Revenues & Tax Stamps

This is interesting,
I reside in the same boat,  but have elected to press on regardless,  I have found if you just post  away, with textual references, someone, somewhere on the internet,
will come and sip at the pool.
The trick is to have enough text in the post to attract the pertinent Google search.

I found that recently with the "Toy Posts",  the results were 5 fold, from my last check on Google 3 years ago.

Because there are no album pages, either for this sort of stuff,  I am always tempted to leave willy nilly in Hagners pages,
yet stuffing them all on a printed page, no matter how haphazard, increases their appeal, and readers response.

I don't think there is a requirement to have knowledge about a discipline in philately, to begin a post,  just  let it all hang out, and see if 
you attract a knowledgeable collector to add to the group's  data bank.

A while back I promised to post some Mexico revenues in this thread. So here, finally, they are.
Back then I said I didn't know much about them. I still don't. So any help will be appreciated.
They're not all revenues, of course, but they are all pre-1940. They're currently housed in my back-back-of-the-book Mexico section of Scott International Vol 1.

I still know very little about these, except that I've noticed that revenues command respectable prices in internet auctions. Thanks, racatrien, for bringing up the topic again.