1. Lai ZY, Sarkanen KV. Isolation and structural studies. In: Sarkanen KV, Ludwig CH, editors. Lignins, occurrence, formation, structure and reactions. New York: Wiley; 1971. p. 165–240.
2. Hatakeyama H, Hatakeyama T. Lignin structure, properties and application. Adv Polym Sci. 2010;232:1–63.
3. Hatakeyama H, Hatakeyama T. Green polyurethanes: molecular design and application. New York: Nova Science Publishers, Inc.; 2016.
4. Norgren M, Edlund H. Lignin: recent advances and emerging applications. Curr Opin Colloid Inter Sci. 2014;19:409–16.
5. Lebo SE, Braten SM, Fredheim GE, Lutnaes BF, et al. Recent advances in the characterization of lignosulfonates. In: Hu TQ, editor. Chemical modification and usage of lignin. New York: Kluwer Academic Publishers; 2002. p. 189–205.