Arndt, Hans-Dieter; Knoll, Andrea; Koert, Ulrich Angewandte Chemie - International Edition, 2001, vol. 40, # 11 p. 2076 - 2078 doi: 10.1002/1521-3773(20010601)40:11<2076::AID-ANIE2076>3.0.CO;2-G