Jang YH, Yang SY, Jang YJ, Park C, Kim JK, and Kim DH. Chem. Eur. J. Ultrahigh Density Arrays of Toroidal ZnO Nanostructures by One-Step Cooperative Self-Assembly Processes: Mechanism of Structural Evolution and Hybridization with Au Nanoparticles. 2011; 17:2068-76.