Petuskova, J., Bruns, H., & Alcarazo, M. (2011). Cyclopropenylylidene-Stabilized Diaryl and Dialkyl Phosphenium Cations: Applications in Homogeneous Gold Catalysis. Angewandte Chemie-International Edition, 50, 3799-3802. doi:10.1002/anie.201100338.