Y. Liu, N. Gu, Y. Liu, X. Ma, P. Liu, and J. Xie, “3-(Diphenylphosphino)propanoic Acid: An Efficient Ligand for Cu-Catalyzed N-Arylations of Indoles and Aryl Amines”, ajc, vol. 27, no. 3, pp. 1075–1078, Jan. 2015.