Chen, Guangmei, et al. “Synthesis of Acrylic Acid Polyurethane Hybrid Emulsions and Characterization on the Properties for Acrylic Acid Polyurethane Films”. Asian Journal of Chemistry, vol. 24, no. 9, May 2012, pp. 3954-6, https://asianpubs.org/index.php/ajchem/article/view/9511.