Stacking-fault double-ribbons were observed, and values for the extrinsic and intrinsic stacking-fault energies (41.2 and 46.5mJ/m2, respectively) were obtained from the widths of the ribbons. The ratio of the intrinsic to extrinsic stacking-fault energy was found to be 1.13. Observation of Double Ribbons in GaAs and AlGaAs. S.McKernan, G.J.Zhu, C.B.Carter: Philosophical Magazine Letters, 1991, 64[6], 349-55