3Parreira, V. R.T. Yano;Cytotoxin produced by Es- cherichia coli isolated from chickens with swollen head syndrome (SHS) [J];Vet Microbiol, 1998, (62): 111-119.
7Pathanasophon P, Sawada T, Tanticharoenyos T. New serotypes of Riemerella anatipestifer isolated from ducks in Thailand [J]. Avian Pathology, 1995, 24 : 195-199.
8Ryll M, Hinz K H. Exclusion of strain 620/89 as type strain for serovar 20 of Riemerella anatipestifer [J]. Berl Munch Tierarztl Wochenschr, 2000,113 (2) : 65.
9Sandhu T S, Leister M L. Serotypes of Pasteurella anatipestiler isolates from poultry in different countries[J]. Avian Pathology, 1991, 20:233-239.
10Loh H, Teo T P, Tan H C. Serotypes of PasteureUa anatipestifer isolates from ducks in Singapore: a proposal of new serotypes[J]. Avian Pathology, 1992, 21:453-459.