7Mengeling W L, Pejsak Z,Paul P S. Biological assay of attenuated strain NADL-2 and virulent strain NADL8 of porcine parvovirus [J].Am J Vet Res,1984,45(11) :2403 - 2407.
8Fujisaki Y,Murakami Y,Suzuki B. Establishment of an attenuated strain of porcine parvovirus by serial passage at low temperature [J]. Natl Inst Anita Health Q(Tokyo), 1982,22 ( 1 ):1 - 7.
9Fujisaki Y,Murakami Y. Immunity to infection with porcine parvorius in pigs inoculated with the attenuated HT-strain[J]. Natl Inst Anim health Q(Tokyo) ,1982,22(1) :36 - 37.
