@article{graham1989,
  title={Concrete Mathematics: A Foundation for Computer Science},
  author={Ronald Graham and Donald E. Knuth and Oren Patashnik and Stanley Yung‐Chuan Liu},
  year={1989},
  journal={Computers in Physics},
  doi={10.1063/1.4822863},
  url={https://doi.org/10.1063/1.4822863}
}