1. An algorithm for finding the blocks of a permutation group;Atkinson;Math. Comp.,1975
2. The maximal subgroups of the sporadic simple group of Held;Butler;J. Algebra,1981
3. Computing in permutation and matrix groups I: normal closure, commutator subgroup, series;Butler;Math. Comp.,1982
4. Computing in permutation and matrix groups II: backtrack algorithm;Butler;Math. Comp.,1982
5. Gregory Butler and John J. Cannon, Computing in permutation and matrix groups III: Sylow subgroups, manuscript.