Freely Indecomposable Groups Acting on Hyperbolic Spaces. - Ilya Kapovich; Richard Weidmann (Int. J. Algebra Comput., 2004)

Foldings, Graphs of Groups and the Membership Problem. - Ilya Kapovich; Richard Weidmann; Alexei G. Myasnikov (Int. J. Algebra Comput., 2005)