A Characterization of Motions as Bijections Preserving Inradius or Circumradius One. J.A. Lester — 1986 Monatshefte für Mathematik
On distance preserving transformations of lines in Euclidean three-space. J.A. Lester — 1985 Aequationes mathematicae
Transformations of Robertson-Walker spacetimes preserving separation zero. J.A. Lester — 1982 Aequationes mathematicae