International
Tables for Crystallography Volume A Spacegroup symmetry Edited by M. I. Aroyo © International Union of Crystallography 2015 
International Tables for Crystallography (2015). Vol. A, ch. 1.4, p. 70
Figure 1.4.5.2
B. Souvignier^{d}


Figure 1.4.5.2
Symmetryelement diagrams for the space group (31) for orthogonal projections along [100] (left), [010] (middle) and [001] (right). 