@article{1965,
  title={Equations of Mathematical Physics},
  author={А. Н. Тихонов and A. A. Samarskiĭ and Peter B. Kahn},
  year={1965},
  journal={American Journal of Physics},
  doi={10.1119/1.1971985},
  url={https://doi.org/10.1119/1.1971985}
}