Crookes 1909 (EN) W. Crookes, On Scandium, in Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character, vol. 209, n. 441-458, 1909, pp. 15-46, DOI:10.1098/rsta.1909.0002.
Cotton 2006 (EN) S.A. Cotton, Scandium, Yttrium & the Lanthanides: Inorganic & Coordination Chemistry, in Encyclopedia of Inorganic Chemistry, 2ª ed., John Wiley & Sons, 2006, DOI:10.1002/0470862106.ia211, ISBN9780470862100.
oadoi.org
Crookes 1909 (EN) W. Crookes, On Scandium, in Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character, vol. 209, n. 441-458, 1909, pp. 15-46, DOI:10.1098/rsta.1909.0002.