Becker, R., Pap, G., MacHner, A., & Neumann, W. H. (2002). Strength and motion after hemiarthroplasty in displaced four-fragment fracture of the proximal humerus: 27 patients followed for 1-6 years. Acta Orthopaedica, 73(1), 44–49. https://doi.org/10.1080/000164702317281396