Help With FDC Russian Philatelic Society In China -Shanghai

Hello all,
This cover was part of a small collection of world covers obtained a couple months ago. Cannot find an online catalog relating to this cover.
It states : In Commemoration of the Retrocession of the International Settlement of Shanghai August 1st, 1943.







Any information will be appreciated.

Thanks,
nodeli

Nodeli I'm sorry I cannot help on I'd of the cover, but had to say I absolutely love that huge blue/purple cancel. And the other post marks are nice and clear. Very nice color on that orange stamp as well. Nice.

Nodeli, if you try Googling China and Unequal Treaties, and British Concession and French Concession in Shanghai, you'll find the background to this (rather hollow) retrocession.

Somewhat unrelated to the FDC, you can read some fascinating information about the "Russian Philatelic Society in China" in an old (1957) article in the Rossica Journal here:

http://ufdc.ufl.edu/UF00020235/00029/30j

Thanks for all the advice and info. With your help and the help of others, the stamps were identified as Gibbons #8-11 within the "Nanking and Shanghai" section ("D.") of "Japanese Occupation of China," page 211 in the new Gibbons Part 17. Loose they list at 5.50 British pounds.
As for the cover, it will sit a little longer in my collection. A wise dealer says this area should be blossoming in the near future. I will do some more reading as tonymacg and vasia have given some good advice there. Thanks BAYERN1kreuzer for your input as well.