D. Kumar, A. Syamal, V. Pandey, and M. Rani, “Studies on Polystyrene-Anchored Coordination Compounds of Divalent, Trivalent, Tetravalent and Hexavalent Metal Ions with the Schiff Base Obtained from the Condensation of 3-Formylsalicylic Acid and o-Hydroxyphenylurea”, ajc, vol. 23, no. 11, pp. 5004–5008, Sep. 2011.