Brown H P,Rathjen A H and Tribe D E.Rare earth elements in biological systems [A]. In: Handbook on the physics and chemistry of rare earths [C]. Eds.K A Gschneidner Jr.And L Eyring.Elsevier Science Publish ers B. V. 1990. 423－ 424.
[4]
Sabbioni E, Pietra R, Gaglione P, Vocaturo G, Colombo F, Zanoni M, odi F. Long－ term occupational risk of rare earth pnuemoconiosis[J]. Sci Total Environ, 1982, 26: 19－ 32.
[5]
Sax NI. Dangerous properties of industrial materials. New York: Van Nostrand Reinhold, 1984. 2 358－ 2 368.
