An addition structure on incidence matrices of a BIB design

@article{Matsubara2006AnAS,
  title={An addition structure on incidence matrices of a BIB design},
  author={Kazuki Matsubara and Masanori Sawa and D. Matsumoto and H. Kiyama and Sanpei Kageyama},
  journal={Ars Comb.},
  year={2006},
  volume={78}
}