Fizika Tverdogo Tela, 1988 Volume 30, Issue 2,Pages 420–426(Mi ftt4354)
Angular dependence of the electron-spin-resonance line dipole broadening in single crystals containing paramagnetic clusters with anisotropic $g$-tensor: $\mathrm{Er}^{3+}$ in $\mathrm{CaWO}_{4}$