Published with Gap 4: 
 Aclib  Almost Crystallographic Groups. With K. Dekimpe.
GAP page
 Alnuth  ALgebraic NUmber THeory interface.
With B. Assmann and A. Distler.
GAP page
 AutPGrp  Automorphisms finite pgroups. With E. O'Brien.
GAP page
 CrystGAP  Crystallographic groups.
With F. Gaehler and W. Nickel.
GAP page
 Format  Formation theoretic subgroups.
With C.R.B. Wright.
GAP page
 GrpConst  Computing the groups of a given order.
With H.U. Besche.
GAP page
 LiePRing  The Lie rings of order at most p^7.
With M. VaughanLee.
GAP page and some notes
 ModIsom  Automorphisms and Isomorphisms for nilpotent
associative algebras.
GAP page
 Polycyclic  Computing with infinite polycyclic groups.
With M. Horn and W. Nickel
GAP page
 SglPPow  The groups of order 3^8 and p^7.
With M. VaughanLee.
GAP page
 Small Groups  A large library of small groups.
With H.U. Besche and E. O'Brien.
GAP page



Archives of code for Gap 4: 


