J. Wang and Z. Liu, “Preparation and Characterization of Acrylic Acid-Ca-Montmorillonite and Its Application for Preparation of Poly(vinyl acetate)/Montmorillonite Nanocomposite Emulsion by in situ Emulsion Polymerization”, ajc, vol. 25, no. 11, pp. 5935–5940, Jun. 2013.