TY - CPAPER AU - Chang, C.-C.; J. J. Zimmerman and K.-J. Yoon TI - GENETIC AND ANTIGENIC VARIATION OF PRRSV IN PERSISTENTLY INFECTED PIGS T2 - International Pig Veterinary Society Congress DP - American Association of Swine Veterinarians DB - AASV Swine Information Library UR - https://www.aasv.org/library/swineinfo/ PY - 2004 DA - 2004/06/01 L1 - https://www.aasv.org/library/swineinfo/Content/IPVS/2004/355.pdf SE - 1.5. Immunology and Vaccination ER -