Brunswick Braunschweig Envelope Stamps

Hi,
I bought this a year or so ago and had put them aside, as I had no space for them in my German States album. The page is from an album in the 1800"s. I found a very nice article online from the Mercury Stamp Journal, June 1953. The article has quite the history of these envelope stamps. I cannot find, though, any pictures of them online, that I can compare to. I am curious, and would appreciate any comments from the community re: legitimacy of these envelope stamps and their rarity. Thanks (Sorry the first picture is tilted)




*** Moved by Staff to a more appropriate forum. ***

One here

https://www.stampcircuit.com/stamp-...l-stationary

and another if you scroll down.

Michel's Ganzsachen-Katalog Deutschland (Postal Stationery Catalog of Germany area) lists all of the postal stationery envelopes for Braunschweig on two pages.

Generally, German specialists do not collect cut squares or trimmed indica, because many (most?) of the items were prepared in different formats (envelope, wrapper or card size, printing, flap, etc) making specific identification impossible without the complete item.