Cameronʹs construction of two-graphs

Tsaranov and Seidel define a map from trees to two-graphs. Cameron gives another map from C-trees to two-graphs. Covington associates rooted C-trees with N-free graphs. By modifying slightly his method, we define a bijection between rooted C-trees and N-free graphs. Using this, we give a detailed proof of Cameronʹs theorem on construction of two-graphs from C-trees.