Thank you very much for the long quotation. Here is a Google translation :
LEON FAJNER FOR THE MEMBER OF THE NATIONAL COUNCIL SZMUL ZYGIELBOJMA: CONCLUSION ON JUSTIFICATION
Warsaw, 31 August 1942
TO P. ZYGIELBOJMA
MEMBER OF THE COUNCIL OF NARODOWEJ R.P.
1. The need for immediate retaliation against German nationals living in the territories of all allied states threatened with immediate further retaliation in the event of the continued slaughter of the Jewish population; To consider this retaliatory act as an act of non-political but strategic action, because what the German authorities do with the Jewish population is war, sui generis war in which one side - the Nazi band - is armed from head to toe and the other - the Jewish population She was refined, perfidiously and finally disarmed, completely disarmed and helpless, and became the object of unprecedented, cruel and insidious warfare under the banner of Hitler. Jewish society as one of the minor members of the great allied family has the right to demand from the rest of the allies immediate and effective assistance in this uneven war.
2. The referendum by the Government of the Republic of Poland and the National Council to all the free societies of the world, with the presentation of the Nazi horrors made to the Jewish population under the yoke of German fascism, and the call of the respective governments for immediate retaliatory action (see p.
3. Call by the Government of the Republic of Poland and the National Council addressed to the Polish society in the country to provide all assistance to the Jewish population.
4. Appeal to the working class (physical and mental workers and working intelligentsia) of the whole world, depicting the massacre carried out on the Jewish population and the call to exert pressure on their governments towards the postulate of ad. 1. In particular, it is also about asking for the same target for the working class of the Soviet Union, which has a large number of German military and civilian prisoners of war. Tell the German society exactly and the facts of the slaughter.
5. Message by the official authorities of substantial financial assistance to the rest of the Jewish population, completely sterilized and killed for hunger.
6. Refer to the CKB in New York and to the B representative in the Soviet Union, if any, and to B's representations in other countries, if such exist in the above indications and in material assistance.
7. Constant communication with us, immediate information on what has been done and what has been done in the above matters, and information on all other matters of national and international importance. (Sending letters, documents, etc., as well as substantial material deeds similar to letters and documents). All to the hand of the remaining members of the CK. This letter should be immediately communicated to CK in New York and to confirm receipt of the notice here.
PS. The text of the interview given to the contributor of this letter may be communicated to the official readers only after you have reviewed your and CK with her and give it to her.
It seems that the book reproduced only the conclusions of the letter.
You say : "I don't think anybody knows that, or saw the documents, all the references from various history books I know lead to Armia Krajowa w dokumentach 1939-1945 published in 1970. And its authors are probably all dead by now."
I think I must disagree, for Wood and Jankowski, 2014, p. 265, give the following reference for the letter :
Feiner, Leon. "Berezowski" letter to Szmul Zygielbojm (Bund leader in London), August 31, 1942. File A.9.III.2a/5, Polish Institute, London.