Krithiga, K., et al. “Concurrent Infection of Infectious Bronchitis (IB) and Sub-Clinical Infectious Bursal Disease (IBD) in an Organised Poultry Farm”. International Journal of Livestock Research, vol. 9, no. 7, July 2019, pp. 261-6, http://ijlr.org/ojs_journal/index.php/ijlr/article/view/1209.