Yosef Porat (then Heinz Josef Foerder) and Salo Flohr's signatures from the 1935 Olympiad (image credit: Olimpbase).
From Yosef Porat, Aman ha'Sachmat [Yosef Porat, the Chess Master], by Porat and Eliyahu Fasher, p. 12 [My translation -- A.P.]:
The third meeting between them was in the 1935 Warsaw Olympiad. Porat was 1st board for Palestine, Flohr the 1st board for Czechoslovakia. When the game was adjourned Flohr had a slight advantage, and Porat says: "We resumed in the afternoon, and when I got out of my chair for a break I saw the world champion Alekhine, surrounded by a few masters, watching my game. When I asked what has happened, I was told that Flohr, remembering his two previous defeats against me, bet significant sums that he will win [with various players], while Alekhine was one of those who took the bet and had just express his view, that I have good drawing chances. A few moves later Flohr was convinced to agree to a draw."Is there any other information about this incident of betting, or the "substantial sums" involved?