Triangular antiferromagnetic order in the honeycomb layer lattice of ErCl3K. W. Krämer, H. U. Güdel, P. Fischer, F. Fauth, M. T. Fernandez-Diaz and T. HaußEur. Phys. J. B, 18 1 (2000) 39-47DOI: https://doi.org/10.1007/s100510070075