@article{CTT100621213,
  author = {K. Ishida and Y. Kitaoka and Y. Tokunaga and S Matsumoto and K. Asayama and M. Azuma and Z. Hiroi and M. Takano},
  title = {Spin Correlation and Spin Gap in Quasi-One-Dimensional Spin-1/2 Cuprate Oxides: A 63Cu NMR Study},
  journal = {Phys. Rev. B},
  year = 1996,
}