Kuzhivelil Joseph, Arun, and Jayalekshmi Sankaran. “Third Order Nonlinear Optical Constants of L-Alaninium Oxalate”. Photonics Letters of Poland, vol. 7, no. 3, Sept. 2015, pp. pp. 81-83, doi:10.4302/photon. lett. pl.v7i3.596.