International
Tables for Crystallography Volume D Physical properties of crystals Edited by A. Authier © International Union of Crystallography 2013 
International Tables for Crystallography (2013). Vol. D, ch. 2.3, p. 348
Section 2.3.8. Glossary^{a}Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, CZ18221 Prague 8, Czech Republic 
: Greek indices are used for Cartesian components of vectors and tensors (summation over repeated indices is understood).
