Boros, E., Füredi, Z. & Kelly, L.M. Discrete Comput Geom (1989) 4: 345. doi:10.1007/BF02187735
A misstated conjecture in  leads to an interesting “(1, 3) representation” of the 7-point projective plane inR4 where points are represented by lines and planes by 3-spaces. The corrected form of the original conjecture will be negated if there is a (1, 3) representation of the 13-point projective plane inR4 but that matter is not settled.