Yonchev, Yonko, Radka Bozhinova, and Marina Drumeva – Yoncheva. 2014. “Monitoring of Economically Important Virus Diseases in Virginia Tobacco Varieties”. Bulgarian Journal of Crop Science 51 (4-5): 20-23. https://agriacad.eu/ojs/index.php/bjcs/article/view/3691.