Mustafa Gülfen and Yazgı Canbaztrans. 2020. Ratio - First Order Derivative - Zero Crossing UV-Visible Spectrophotometric Method for Analysis of Amoxicillin, Levofloxacin and Lansoprazole Mixture. Pakistan Journal of Analytical & Environmental Chemistry. 21, 1 (Jun. 2020), 34 – 43. DOI:https://doi.org/10.21743/pjaec/2020.06.05.