Nugrahani, Ilma, et al. “THEOPHYLLINE–NA–SACHARRINE SINGLE CRYSTAL ISOLATION FOR ITS STRUCTURE DETERMINATION”. International Journal of Pharmacy and Pharmaceutical Sciences, vol. 7, no. 12, Dec. 2015, pp. 15-24, https://www.journals.innovareacademics.in/index.php/ijpps/article/view/7749.