^Schumann, Herbert; Fedushkin, Igor L., Scandium, Yttrium & The Lanthanides: Organometallic Chemistry which appeared in theEncyclopedia of Inorganic Chemistry, First Edition., Chichester, UK: John Wiley & Sons, Ltd, 2006-03-15, ISBN 0-470-86078-2, doi:10.1002/0470862106.ia212