@article{georgieva-trifonova2021research,
  title={Research Problems and Methods in Big Data Analytics for Knowledge Discovery from Customer Feedback}
  author={Georgieva-Trifonova, Tsvetanka and Galabov, Miroslav and Djonov, Martin}
  journal={ICT Innovations 2021, Web Proceedings ISSN null}
  pages={265--274}
  year={2021}
}