Azuma, Yusuke; Imanishi, Miki; Yoshimura, Tomoyuki; Kawabata, Takeo; Futaki, Shiroh Angewandte Chemie, International Edition, 2009 , vol. 48, # 37 p. 6853 - 6856 Angewandte Chemie, 2009 , vol. 121, # 37 p. 6985 - 6988