I. Matulková, I. Císařová, M. Fridrichová, R. Gyepes, P. Němec, J. Kroupa, and I. Němec. Inorganic Salts of N-phenylbiguanidium(1$\mathplus$){\textemdash}Novel Family with Promising Representatives for Nonlinear Optics. International Journal of Molecular Sciences, MDPI AG, volume 22, issue 16, August 2021. I. Němec, I. Matulková, W. Krumbe, L. Andersen, I. Císařová, J. Kroupa, P. Němec, L. Bohatý, and P. Becker. Linear and nonlinear optical properties, pyroelectricity and vibrational spectroscopy of polar guanidinium hydrogen phosphite, {GuH}2PO3, and hydrogen selenite, {GuHSeO}3. Optical Materials, Elsevier BV, volume 111, January 2021. I. Němec, I. Matulková, P. Held, J. Kroupa, P. Němec, D. Li, L. Bohatý, and P. Becker. Crystal growth, crystal structure, vibrational spectroscopy, linear and nonlinear optical properties of guanidinium phosphates. Optical Materials, volume 69, July 2017.