E. V. Aghababyan, N. P. Harutyunyan, S. A. Nikitin, and N. Y. Pankratov, “MAGNETIC PHASE TRANSITIONS IN (Er$_x$Nd$_{1-x})_2$Fe$_{14}$B H$_{3,4}$ INTERMETALLIC HYDRIDES”, Proc. YSU A: Phys. Math. Sci., vol. 41, no. 2 (213), pp. 64–71, Jun. 2007.