1. G. K. Yagola, V. I. Zingerman, and M. I. Grobovitskii, Author's certificate No. 130977, Byull. Izobr., No. 16 (1960).
2. G. K. Yagola, V. I. Zingerman, M. I. Grobovitskii, and V. N. Sepetyi, izmeritel'. Tekh., No. 1 (1965).
3. GOST 13601-68. Hard-magnetic Materials, Cast. Methods of Determining Static Magnetic Characteristics of Specimens [in Russian].