Basic techniques of combinatorial theory

Classical Topology and Combinatorial Group Theory by John Stillwell

Combinatorial Group Theory: Presentations of Groups in Terms of Generators a...

A Survey of Combinatorial Theory; Srivastava, Jagdish N.:

Cooperative Games on Combinatorial Structures. Theory and Decision Library C, Ba

Applications of Combinatorial Matrix Theory to Laplacian Matrices of Graphs, ...

Combinatorial Group Theory Contemporary Mathematics, 109 Tang, Francis C. Y., Be