@article{CTT100779852,
  author = {Yoshifumi Okuda and Yoshitoshi Tanaka},
  title = {Study of blocking patents and many patents strategy by Japanese big companies},
  journal = {International Journal of Liability and Scientific Enquiry},
  year = 2014,
}

@inproceedings{CTT100787225,
  author = {Yoshifumi Okuda and Yoshitoshi Tanaka},
  title = {What are the critical factors making influences on the selection of patents to be maintained or abandoned, for proper patent portfolio?},
  booktitle = {Information Ethics and Security},
  year = 2014,
}