Stoykova, Slavena, et al. “Role and Significance of Residual Monomer MMA for the Comfort of Patients Using PMA Contact Lenses”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 45, no. 2, May 2019, pp. 196-04, https://gssrr.org/JournalOfBasicAndApplied/article/view/9940.