8Marsh J A, Combs Jr G F, Whitacre M Ejet al. Effect of selenium and vitamin Edietary defciencies on chick lymphoid organ developmentfJ], Proc SocExp Biol Med, 1986,182(4):425 - 536.
9Hogan J S. Efficacy of parenteral vitamin E fortreating bovine mastitis[J]. Agri Prac, 1994,15:29.