https://research.ibm.com/publications/paramagnetic-resonance-of-trivalent-iron-in-single-crystal-potassium-tetrafluoaluminate
Paramagnetic resonance of trivalent iron in single-crystal potassium tetrafluoaluminate for Journal...
Paramagnetic resonance of trivalent iron in single-crystal potassium tetrafluoaluminate for Journal of Applied Physics by H.M. Gladney