D. S. Griffin and R. S. Varga, Numerical solution of plane elasticity problems, J. Soc. Indust. Appl. Math. 11 (1963), 1046-1062. MR 28, 3544. Zbl. 122, p. 189.

1. Introduction. It has been known for some time that the stress distribution
in a plane bounded region with an irregularly shaped boundary may be accurately
approximated by finite difference methods. Indeed, some twenty years ago,
Southwell and his co-workers [1,2] utilized finite difference approximations,
and applied Southwell's "relaxation" method, a *noncyclic* or *
free-steering* iterative procedure, to the approximate solution of
interesting engineering problems. Though this "relaxation" method has been known
to work well when human insight guides the course of calculations on a desk
calculator, such noncyclic iterative techniques become extremely laborious on
desk calculators when results of high precision are required. More damaging is
the fact that such noncyclic iterative techniques can rarely be adapted
efficiently to high-speed digital computers.