@book{Biggs_1989, address={Oxford}, edition={Rev. ed}, title={Discrete mathematics}, publisher={Clarendon}, author={Biggs, Norman}, year={1989} }
@book{Grimaldi_2014, address={Harlow, Essex, England}, edition={Fifth edition}, title={Discrete and combinatorial mathematics: an applied introduction}, url={https://www.vlebooks.com/vleweb/product/openreader?id=AberystUni&isbn=9781292035994}, publisher={Pearson Education Limited}, author={Grimaldi, Ralph P.}, year={2014} }
@book{Liu_1985, address={New York}, edition={2nd ed}, title={Elements of discrete mathematics}, volume={McGraw-Hill computer science series}, publisher={McGraw-Hill}, author={Liu, C. L.}, year={1985} }
@book{Wilson_Watkins_1990, address={New York}, title={Graphs: an introductory approach: a first course in discrete mathematics}, publisher={Wiley}, author={Wilson, Robin J. and Watkins, John J.}, year={1990} }
