Little, Ruby R. “Histology of Barks of Cinchona and Some Related Genera in Colombia. 7 (27): 404-425, 1947”. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 43, no. Supl (November 5, 2019): 144–146. Accessed May 23, 2025. https://raccefyn.co/index.php/raccefyn/article/view/1074.