@article{RenHovenierHigginsetal.2011,
  author    = {Y. Ren and J. N. Hovenier and R. Higgins and J. R. Gao and T. M. Klapwijk and S. C. Shi and B. Klein and T.-Y. Kao and Q. Hu and J. L. Reno},
  title     = {High-resolution heterodyne spectroscopy using a tunable quantum cascade laser around 3.5 THz},
  series   = {Applied Physics Letters},
  volume    = {98},
  number    = {23},
  publisher = {AIP Publishing},
  issn      = {0003-6951},
  doi       = {10.1063/1.3599518},
  year      = {2011},
  language  = {en}
}