Al-Mayyahi, Baqer, et al. “Synthesis, Characterization and Thermal Properties of the Nano Four Arms poly(pentaerythritollactide-B-N,N-Dimethylaminoethyl Methacrylate) Derivatives”. European Journal of Chemistry, vol. 7, no. 4, Dec. 2016, pp. 405-9, doi:10.5155/eurjchem.7.4.405-409.1480.