@article{graneheim2003,
  title={Qualitative content analysis in nursing research: concepts, procedures and measures to achieve trustworthiness},
  author={Ulla Hällgren Graneheim and Berit Lundman},
  year={2003},
  journal={Nurse Education Today},
  doi={10.1016/j.nedt.2003.10.001},
  url={https://doi.org/10.1016/j.nedt.2003.10.001}
}