Senthamil Selvan, P., R. Gopinath, V.S. Saravanan, and N. Gopal. 2010. “Simultaneous Estimation of Levocetirizine, Ambroxol, Phenylpropanolamine and Paracetamol in Combined Dosage Forms by RP-HPLC Method”. Asian Journal of Chemistry 18 (4):2591-96. https://asianpubs.org/index.php/ajchem/article/view/20624.