  
  
  [1XReferences[0X
  
  [[20XAHU74[15X]  [16XAho,  A.  V., Hopcroft, J. E. and Ullman, J. D.[15X, [17XThe Design and
  Analisys of Computer Algorithms[15X, Addison-Wesley, Reading, Mass. (1974).
  
  [[20XDEGKNW02[15X]  [16XDobkin,  D., Ellson, J., Gansner, E., Koutsofios, E., North,
  S.  and  Woodhull, G.[15X, [17XGraphviz - Graph Drawing Programs[15X, AT\&T Research
  and            Lucent            Bell            Labs            (2002),
  (((http://www.research.att.com/sw/tools/graphviz))).
  
  [[20XHU69[15X]  [16XHopcroft,  J.  E.  and Ullman, J. D.[15X, [17XFormal Languages and their
  Relation to Automata[15X, Addison-Wesley, Reading, Mass. (1969).
  
  [[20XKM02[15X]  [16XKapovich, I. and Myasnikov, A.[15X, [17XStallings foldings and subgroups
  of free groups[15X, [18XJ. of Algebra[15X, [19X248[15X (2002), 608--668.
  
  [[20XMSW01[15X]  [16XMargolis, S., Sapir, M. and Weil, P.[15X, [17XClosed subgroups in pro-V
  topologies  and  the  extension problem for inverse automata[15X, [18XInt. J. of
  Algebra and Computation[15X, [19X11[15X (2001), 405--445.
  
  [[20XMMPTV95[15X]  [16XMatz,  O.,  Miller, A., Potthoff, A., Thomas, W. and Valkema,
  E.[15X,  [17XReport  on  the program AMoRe[15X, Christian Albrechts Universit{\"a}t,
  Kiel, 9507 (1995).
  
  
  
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