H Bass, Group
actions on non–Archimedean trees, from: "Arboreal group
theory (Berkeley, CA, 1988)", Math. Sci. Res. Inst. Publ. 19,
Springer (1991) 69 MR1105330
I M Chiswell,
Harrison's theorem for $\Lambda$–trees, Quart. J. Math.
Oxford Ser. $(2)$ 45 (1994) 1 MR1269285
10
I M Chiswell,
Introduction to $\Lambda$–trees, from: "Semigroups,
formal languages and groups (York, 1993)", NATO Adv. Sci. Inst.
Ser. C Math. Phys. Sci. 466, Kluwer Acad. Publ. (1995) 255
MR1630624
11
I Chiswell,
Introduction to $\Lambda$–trees, World Scientific
Publishing Co. (2001) MR1851337
A M Gaglione,
D Spellman, Every “universally free” group is
tree-free, from: "Group theory (Granville, OH, 1992)",
World Sci. Publ., River Edge, NJ (1993) 149 MR1348896
15
A M Gaglione,
D Spellman, Does Lyndon's length function imply the
universal theory of free groups?, from: "The mathematical
legacy of Wilhelm Magnus: groups, geometry and special
functions (Brooklyn, NY, 1992)", Contemp. Math. 169, Amer.
Math. Soc. (1994) 277 MR1292905
16
S Gross, Group
actions on $\Lambda$–trees, PhD thesis, Hebrew University,
Jerusalem (1998)
17
V Guirardel, Rips
theory for actions of finitely generated groups on
$\mathbb{R}$–trees, in preparation
O Kharlampovich, A
Myasnikov, Irreducible affine varieties over a free
group I: Irreducibility of quadratic equations and
Nullstellensatz, J. Algebra 200 (1998) 472 MR1610660
21
O Kharlampovich, A
Myasnikov, Irreducible affine varieties over a free
group II: Systems in triangular quasi-quadratic form and
description of residually free groups, J. Algebra 200
(1998) 517 MR1610664
F Paulin, Sur la
théorie élémentaire des groupes libres (d'après Sela),
Astérisque (2004) 363 MR2111650
25
P H Pfander,
Finitely generated subgroups of the free
$\mathbb{Z}[t]$–group on two generators, from: "Model
theory of groups and automorphism groups (Blaubeuren, 1995)",
London Math. Soc. Lecture Note Ser. 244, Cambridge Univ. Press
(1997) 166 MR1689871