D. Gao, H. Sun, J. Si, H. Chen, D. Zhu, and J. Shi, “Ultrasensitive Detection of 2,4-D at Surface of a Hybrid Silica Nanoparticle Based on Photoinduced-Electron Transfer Enhanced Fluorescence”, ajc, vol. 24, no. 9, pp. 4031–4034, May 2012.