US : Poster Stamps And Cinderellas.

Recently picked this up in auction. I found no listing in the Fields-Picklo Catalog of Cinderellas. Does anyone have any information on the "Stamp Trade Protective Association"? Who were they? From where did they operate? Any help is appreciated.

STAMP TRADE PROTECTIVE ASSOCIATION

XXXX LABEL: ROUND DIE CUT. GREEN ON WHITE. TITLE IN CIRCLE, WITH RAYS COMING
OUT OF S.T.P.A. LOGO. IMPERF/GUMMED. 30 MM $ 2.00

https://alphabetilately.org/philexpo/phil~dlr.htm

THE AMERICAN PHILATELIST. 7

ANOTHER FORGERY EXPOSED.

Mr. W. Hadlow of London, England, well known philatelic auctioneer of
Messrs. Plumridge & Co. and member of the Expert Committee, The Stamp Trade Protective Association, notwithstanding his many professional duties finds time for an intensive study and research of stamps for his own pleasure and that of the readers of the "Stamp Collectors Fortnightly" to which he liberally contributes. Through his courtesy we are able to illustrate here a clever and in a
sense, dangerous forgery of the first issue Austrian Lombardy, Scott's No. 1. Mr. Hadlow has made a number of interesting type discoveries in early Austrian issues and thought he had made another when he came across the two stamps illustrated at the left. He noted t

Philatelic West 1910
https://archive.org/stream/philatel...020_djvu.txt

I am in a position to supply fine Itnperf. Part perf. U. S. REVE¬
NUES at half Scott's Catalog price. In finest stock in this country.
New lists of wants with references, first come, first served, as
this is the first time I have advertised in the American papers.
Selections of the medium varieties that is to $1 in value sent on
approval against cash or exchange. My specialty is books of
Bri:ish Colonies.all picked copies at 50 percent off Gibbons about
equal to Scott. Give me a trial and you wont be disappointed.
Member of the Stamp Trade Protective Association, S. P.A. and
various other Societies, Reference, L. T. Brodstone, and any
o*her prominent American Dealers. Send your Want List today.