Nizam Ahmad, Shahrul, et al. “Tetradentate Palladium(II) Salophen Complexes: Synthesis, Characterization and Catalytic Activities in Copper-Free Sonogashira Coupling Reaction”. International Journal of Engineering & Technology, vol. 7, no. 3.11, July 2018, pp. 15-19, https://doi.org/10.14419/ijet.v7i3.11.15921.