@article{parkinson:1969:opl,
    author = {J. B. Parkinson},
     title = {Optical properties of layer antiferromagnets with
            $\mathrm{K}_2\mathrm{NiF}_4$ structure},
   journal = {J. Phys. C: Solid State Physics},
    volume = {2},
    number = {11},
     pages = {2012–2021},
      year = {1969},
       doi = {10.1088/0022-3719/2/11/316}}