Angelova, S. G., I. L. Georgieva, A. A. Teodosieva, and N. S. Korsun. 2015. “Neuraminidase Inhibitor Susceptibility of Influenza Viruses Circulating in Bulgaria During the Last Four Consecutive Epidemic Seasons (2011/12 to 2014/15)”. American Scientific Research Journal for Engineering, Technology, and Sciences 12 (1):162-69. https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/748.