Add References

Author: FriedrichRober

doc/intro.xml

@@ -11,8 +11,9 @@ The package &LINS; provides an algorithm for computing the normal subgroups of a
 Moreover it provides an interface for searching in the normal subgroup lattice of a finitely presented group.
 For example, one can use this interface to search for <M>l</M> normal subgroups of index <M>n</M>. <P/>
 
-The algorithm is based on work of Derek Holt and David Firth.
-They have implemented this algorithm in the algebra software MAGMA. <P/>
+The algorithm is based on work of David Firth <Cite Key="Firth"/>.
+He implemented this algorithm in the algebra software MAGMA.
+This implementation has been revised and rewritten to a great extent by Derek Holt. <P/>
 
 The current implementation in &GAP; uses a table of groups that was computed by the code in <F>createTables.gi</F>.
 

doc/lins.bib

@@ -0,0 +1,7 @@
+@phdthesis{Firth,
+ type       = {Ph.D. thesis},
+ author     = {David Firth},
+ title      = {An Algorithm to Find Normal Subgroups of a Finitely Presented Group, up to a Given Finite Index},
+ year       = {2005},
+ school     = {University of Warwick},
+}