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. 3.4, p. 496
Figure 3.4.2.4^{a}Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, CZ18221 Prague 8, Czech Republic, and ^{b}Department of Mathematics and Didactics of Mathematics, Technical University of Liberec, Hálkova 6, 461 17 Liberec 1, Czech Republic 

Figure 3.4.2.4
Oriented symmetry operations of the hexagonal group and of its hexagonal and trigonal subgroups. The coordinate system corresponds to the Cartesian crystallophysical coordinate system, the axes of the crystallographic coordinate system are parallel to the twofold rotation axes and to the sixfold rotation axis . Correlation with other notations is given in Table 3.4.2.6. 