Zr(NO3)4: A Versatile Oxidizing Agent for Aromatization of Hantzsch 1,4-Dihydropyridines and 1,3,5-Trisubstituted Pyrazolines - Sabitha, Gowravaram; Kumar Reddy, G S K; Reddy, Ch Srinivas; Fatima, Narjis; Yadav, J S (Synthesis, 2003)