Optical detection of NADH based on biocatalytic growth of Au–Ag core–shell nanoparticles - Tang, Lin; Lei, Xiaoxia; Zeng, Guangming; Liu, Yuanyuan; Peng, Yanrong; Wu, Mengshi; Zhang, Yi; Liu, Can; Li, Zhen; Shen, Guoli (Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy, 2012)