@article{oliver1992,
  title={An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments},
  author={W. C. Oliver and George M. Pharr},
  year={1992},
  journal={Journal of materials research/Pratt's guide to venture capital sources},
  doi={10.1557/jmr.1992.1564},
  url={https://doi.org/10.1557/jmr.1992.1564}
}