I am actually studying coset geometries (in the sense of Tits and Buekenhout) for the sporadic simple group of Suzuki. I came aware that Buekenhout found in 1979 a geometry over the following diagram

      c          6
O----------O----------O
1          4          4

However, I couldn't find any information about the maximal (or minimal) parabolic subgroups of this geometry.

Has anyone ever studied this geometry? Is there a paper where I could find the informations I am looking for?

As usual, thanks in advance!