@INPROCEEDINGS{tsutomu2021word,
  author={Ito, Tsutomu and Harakawa, Ryosuke and Iwahashi, Masahiro},
  booktitle={2021 IEEE 10th Global Conference on Consumer Electronics (GCCE)}, 
  title={Word Clustering Using Graphical Lasso-Guided PCA for Trend Analysis of COVID-19}, 
  year={2021},
  volume={},
  number={},
  pages={200-201},
  doi={10.1109/GCCE53005.2021.9621893}
}