The Maximum Number of Second Smallest Distances in Finite Planar Sets. P. Brass (1992) Discrete & computational geometry
The maximum number of unit distances among n points in dimension four. van Wamelen, Paul (1999) Beiträge zur Algebra und Geometrie
The Maximum Size of a Convex Polygon in a Restricted Set of Points in the Plane. N. Alon, M. Katchalski, W.R. Pulleyblank (1989) Discrete & computational geometry
The Number of Different Distances Determined by a Set of Points in the Euclidean Plane. F.R.K. Chung, E. Szemeredi, W.T. Trotter (1992) Discrete & computational geometry