Reference

Christoph J. Piribauer, Sven Sindern, Dobromir Mashev, F. Michael Meyer, diverse (2011): Postmagmatic evolution of the Caeira-Pegmatite - a new occurrence and its potential for high-tech-metals in the Bororema Pegmatite Province, NE-Brazil – Berichte der Geologischen Bundesanstalt – 87: 162 - 163.