Derrah, E. J., Pantazis, D. A., McDonald, R., & Rosenberg, L. (2010). Concerted [2+2] Cycloaddition of Alkenes to a Ruthenium–Phosphorus Double Bond. Angewandte Chemie International Edition, 49(19), 3367-3370. doi:10.1002/anie.201000356.