Beleznay, Ferenc; Foreman, Matthew (1995). "The collection of distal flows is not Borel". American Journal of Mathematics. 117 (1): 203–239. doi:10.2307/2375041. JSTOR2375041.
Beleznay, Ferenc; Foreman, Matthew (1995). "The collection of distal flows is not Borel". American Journal of Mathematics. 117 (1): 203–239. doi:10.2307/2375041. JSTOR2375041.