ERIC B. SENGEH, ROMANUS N. NJONG AND OFFIONG E. OFFIONG, F. M.-M. E. N. N. 3.3.2. Synthesis, crystal structure and biological activity of 1-(phthalazin-1(2H)-one)[(Pyridin-2-yl)ethylidene]hydrazone and its cobalt (III) complex. Communications in Inorganic Synthesis, v. 3, n. 3, 11.