Diez, Elena; Dixon, Darren J.; Ley, Steven V. Angewandte Chemie - International Edition, 2001, vol. 40, # 15 p. 2906 - 2909 doi: 10.1002/1521-3773(20010803)40:15<2906::AID-ANIE2906>3.0.CO;2-5