International
Tables for
Crystallography
Volume A
Space-group symmetry
Edited by M. I. Aroyo

International Tables for Crystallography (2016). Vol. A, ch. 1.7, p. 133

Figure 1.7.1.1 

H. Wondratscheka
[Figure 1.7.1.1]
Figure 1.7.1.1

Space group [P6_3/mcm] with t-subgroups of index 2 and 4. All 21 possible subgroup chains are displayed by lines.