Landolt — Bornstein. Numerical Data and Functional Relationships in Science and Technology. New Series. Group HI: Crystal and Solid State Physics. V. 12: Supplement and Extention to Volume 4. Magnetic and Other Properties of Oxides and Related Compounds. Part c: Hexagonal Ferrites, Special Lanthanide and Actinide Compounds.— Berlin; Heidelberg; New York: Springer-Verlag, 1982.— 604 p.