Yogam F, Vetha Potheher I, Vimalan M, Jeyasekaran R, Rajesh Kumar T, Sagayaraj P. Growth and physicochemical properties of l-phenylalaninium maleate: A novel nonlinear optical crystal. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2012 Sep;95():369–73. doi: 10.1016/j.saa.2012.03.088.