1. On a special class of 𝑝-groups;Blackburn, N.;Acta Math.,1958
2. Wieb Bosma and John Cannon (1997), Handbook of Magma functions. School of Mathematics and Statistics, Sydney University.
3. Wiley Monographs in Crystallography;Brown, Harold,1978
4. Helga Finken (1979), “Raumgruppen und Serien von 𝑝-Gruppen”. Staatsexamensarbeit, RWTH Aachen.