@article{CTT100568023,
  author = {T. Yamaguchi and Kuramitsu Nishihara and H. Matsuo and Y. Wang and M. Hashimoto and H. Hachiya},
  title = {A Method of Indoor Target Detection Using M-Sequence Acoustic Signal},
  journal = {Acoustical Imaging},
  year = 2008,
}

@article{CTT100591640,
  author = {Kuramitsu Nishihara and Tadashi Yamaguchi and Hiroyuki Hachiya},
  title = {Position detection of small objects in indoor environments using coded acoustic signal},
  journal = {Acoust. Sci. Technol.},
  year = 2008,
}