International
Tables for Crystallography Volume B Reciprocal space Edited by U. Shmueli © International Union of Crystallography 2010 
International Tables for Crystallography (2010). Vol. B, ch. 5.1, p. 627
Figure 5.1.2.1^{a}Institut de Minéralogie et de la Physique des Milieux Condensés, Bâtiment 7, 140 rue de Lourmel, 75015 Paris, France 

Figure 5.1.2.1
Bragg reflection. (a) Direct space. Bragg reflection of a wave of wavevector incident on a set of lattice planes of spacing d. The reflected wavevector is . Bragg's law can also be written , where is the inverse of the length of the corresponding reciprocallattice vector (see part b). (b) Reciprocal space. P is the tie point of the wavefield consisting of the incident wave and the reflected wave . Note that the wavevectors are oriented towards the tie point. 