1. A. Narath, Phys. Rev.136A (1969) 766.
2. A. Schenck, K.M. Crowe, Phys. Rev. Lett.26 (1971) 57.
3. The first measurements were done on crystals obtained from A. Narath. Since CoCl2·2H2O is hygroscopic and changes to CoCl2·6H2O if not kept dry, it was feared that the samples might have deteriorated over the years. However, subsequent measurements in newly grown crystals gave identical results.
4. N.J. Poulis et al., Physica24 (1958) 280.