1. 24 Theissen Heiko , ‘Eine Methode zur Normalisatorberechnung in Permutationsgruppen mit Anwendungen in der Konstruktion primitiver Gruppen’, Dissertation, Rheinisch Westfälische Technische Hochschule, Aachen, Germany, 1997.
2. Computing Subgroups Invariant Under a Set of Automorphisms
3. Testing for isomorphism between finitely presented groups
4. 6 THE GAP GROUP, GAP- Groups, Algorithms, and Programming, Version 4.3 (The GAP Group, Aachen⁄St Andrews, 2002); http://www.gap-system.org.
5. Computing Matrix Group Decompositions with Respect to a Normal Subgroup