\Bibitem{Bul86} \by L.~N.~Bulaevskii \paper The theory of magnetism \jour UFN \yr 1986 \vol 150 \issue 2 \pages 331 \mathnet{http://mi.mathnet.ru/ufn8193} \crossref{https://doi.org/10.3367/UFNr.0150.198610k.0331}