Molecular Characterization of Major Structural Protein Genes of Avian Coronavirus Infectious Bronchitis Virus Isolates in Southern China oleh Mei-Lan Mo, Meng Li, Bai-Cheng Huang, Wen-Sheng Fan, Ping Wei, Tian-Chao Wei, Qiu-Ying Cheng, Zheng-Ji Wei, Ya-Hui Lang