1. Characterization of pulping liquors;Niemelä,1999
2. K. Niemelä, Biorefining opportunities in the pulp and paper industry, in: Proceedings of the 5th European Biorefinery Symposium, Flensburg, 2008.
3. Copolymerization of glycolic, d,l-lactic and d,l-2-hydroxybutyric acid mixtures present in kraft black liquors;Mehtiö;Eur. Polym. J.,2012
4. S. Wang, Y. Huang, Process for Production of Molecular Weight Polyhydroxy Acid, Singapore, C08G 63/00, WO/2008/036049, 2008.
5. α-Hydroxy acids, β-hydroxy acid, and other topical agents;Draelos;Dermatol. Ther.,2000