It was demonstrated that the shape of a dislocation shear loop, when held in stable equilibrium by an infinitesimal shear loop of the same sign at its centre, was a circle. This unexpected result was suggested to explain certain discrepancies between the loop shapes which were predicted by De Wit and Koehler and those which were observed experimentally.

On the Shape of a Dislocation Shear Loop in Stable Equilibrium. L.M.Brown: Philosophical Magazine Letters, 2001, 81[9], 617-21