Castelli, Fabio, and Renato Contillo. “Using a Chlorophyll Meter to Evaluate the Nitrogen Leaf Content in Flue-Cured Tobacco (Nicotiana Tabacum L.)”. Italian Journal of Agronomy 4, no. 2 (June 30, 2009): 3–12. Accessed August 3, 2025. https://agronomy.pagepress.org/index.php/agro/article/view/ija.2009.2.3.