Determination of Phosphodiesterase Type 5 Enzyme (PDE-5) Inhibitors and Analogues as Adulterants in Selected Herbal Products using Gas Chromatography–Electron Impact-Mass Spectrometer (GC-EI-MS). (2020). Baghdad Science Journal, 17(4), 1190. https://doi.org/10.21123/bsj.2020.17.4.1190