The callus fracture sign: a radiological predictor of progression to hypertrophic non-union in diaphyseal tibial fractures. - Salih, S.; Blakey, C.; Chan, D.; McGregor-Riley, J. C.; Royston, S. L.; Gowlett, S.; Moore, D.; Dennison, M. G. (Strategies in Trauma & Limb Reconstruction, 2015)