@article{bender1991,
  title={Concrete Mathematics: A Foundation for Computer Science.},
  author={Edward A. Bender and Ronald Graham and Donald E. Knuth and Oren Patashnik},
  year={1991},
  journal={American Mathematical Monthly},
  doi={10.2307/2324448},
  url={https://doi.org/10.2307/2324448}
}