[1] Franzone JS, et al. Pharmacological and toxicological activities of a new methylxanthine derivative [7-(1,3-dithiolan-2-ylmethyl)1,3-dimethylxanthine] with antibronchospastic and mucoregulatory properties. Drugs Exp Clin Res. 1990;16(6):263-76. PMID:1964891