Watumlawar, Ega Cyntia, and Byung-Dae Park. “Crosslinking of Hardwood Lignin With Citric Acid for Sustainable Wood Adhesives”. Journal of Research Updates in Polymer Science 14 (June 28, 2025): 62–70. Accessed June 30, 2025. https://mail.lifescienceglobal.com/pms/index.php/jrups/article/view/10322.