- Graham Ellis and Irina Kholodna, Computing second cohomology of finite groups with trivial coefficients, Homology Homotopy Appl. 1 (1999), 163–168 (electronic).[MR]
- Graham Ellis and Irina Kholodna, Three-dimensional presentations for the groups of order at most 30, LMS J. Comput. Math. 2 (1999), 93–117+2 appendixes (HTML and source code) (electronic).[MR]