International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2010). Vol. B, ch. 2.5, p. 384

Figure 2.5.7.4 

P. A. Penczekg
[Figure 2.5.7.4]
Figure 2.5.7.4

Schematic of the 3D projection-alignment procedure.