Spatial networks

I am studying different kinds of optimality property for networks over n given points in two-dimensional space.

Here are the technical papers so far:

Short-length routes in low-cost networks via Poisson line patterns (with Wilf Kendall).
Spatial Transportation Networks with Transfer Costs: Asymptotic Optimality of Hub and Spoke Models.
Optimal spatial transportation networks where link-costs are sublinear in link-capacity

Somewhat related are Percolating paths through random points and Optimal flow through the disordered lattice.