L. Singh, N. Tyagi, N. P. Dhaka, and S. Sindhu, “Synthesis, Spectral and Thermal Studies of Some Lanthanide (III) Complexes of 4-[N-(Benzalidene) Amino] Antipyrine Thiosemicarbazone”, ajc, vol. 11, no. 2, pp. 503–508, Mar. 2010.