A Four-Color Theorem for Periodic Tilings
 
D.H. Huson
 
 
Abstract:
There exist exactly 4044 topological types of 4-colorable
tile-4-transitive tilings of the plane.
These can be obtained by systematic application of two geometric
algorithms, edge-contraction and vertex-truncation, to all tile-3-transitive
tilings of the plane.

Appeared in: Geometriae Dedicata, 51:47-61 (1994)