Medical philately (medical theme on stamps). Donders--father of clinical refraction.

@article{Paidhungat2010MedicalP,
  title={Medical philately (medical theme on stamps). Donders--father of clinical refraction.},
  author={J V Pai-dhungat and Falguni S. Parikh},
  journal={The Journal of the Association of Physicians of India},
  year={2010},
  volume={58},
  pages={55}
}