@article{granja2015transportable,
  author = {Granja, C. and Slav{\'i}{\v{c}}ek, T. and Kroupa, M. and Owens, A. and Posp{\'i}{\v{s}}il, S. and Janout, Z. and Kralik, M. and Solc, J. and Valach, O.},
  title = {A transportable source of gamma rays with discrete energies and wide range for calibration and on-site testing of gamma-ray detectors},
  journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  publisher = {Elsevier BV},
  volume = {771},
  pages = {1--9},
  year = {2015},
  doi = {10.1016/j.nima.2014.10.001},
  issn = {0168-9002}
}